FAHLERZ. Gray copper-ore, called also Panabase, from the many oxides it
contains.
FAINTS, is the name of the impure spirit, which comes over first and
last in the distillation of whiskey; the former being called the
_strong_, and the latter, which is much more abundant, the _weak_
faints. This crude spirit is much impregnated with fetid essential oil,
is therefore very unwholesome, and must be purified by rectification.
FAN (_Eventail_, Fr.; _Fächer_, Germ.); is usually a semi-circular piece
of silk or paper, pasted double, enclosing slender slips of wood, ivory,
tortoise-shell, whale-bone, &c., arranged like the tail of a peacock in
a radiating form, and susceptible of being folded together, and expanded
at pleasure. This well-known hand ornament is used by ladies to cool
their faces by agitating the air. Fans made of feathers, like the wing
of a bird, have been employed from time immemorial by the natives of
tropical countries.
_Fan_ is also the name of the apparatus for winnowing corn. For an
account of the powerful blowing and ventilating fan machine, see FOUNDRY
and VENTILATOR.
FARINA (_Farine_, Fr.; _Mehl_, Germ.); is the flour of any species of
corn, or starchy root, such as potato, arrow root, &c. See BREAD and
STARCH.
FATS, (_Graisses_, Fr.; _Fette_, Germ.) occur in a great number of the
animal tissues, being abundant under the skin in what is called the
cellular membrane, round the kidneys, in the folds of the omentum, at
the base of the heart, in the mediastinum, the mesenteric web, as well
as upon the surface of the intestines, and among many of the muscles.
They vary in consistence, colour, and smell, according to the animals
from which they are obtained; thus, they are generally fluid in the
cetaceous tribes, soft and rank-flavoured in the carnivorous, solid and
nearly scentless in the ruminants, usually white and copious in well-fed
young animals; yellowish and more scanty in the old. Their consistence
varies also according to the organ of their production; being firmer
under the skin, and in the neighbourhood of the kidneys, than among the
movable viscera. Fat forms about one twentieth of the weight of a
healthy animal. But as taken out by the butcher it is not pure, for
being of a vesicular structure it is always enclosed in membranes, mixed
with blood, blood-vessels, lymphatics, &c. These foreign matters must
first be separated in some measure mechanically, after the fat is minced
small, and then more completely by melting it along with hot water,
passing it through a sieve, and letting the whole cool very slowly. By
this means a cake of cleansed fat will be obtained. Many plans of
purifying fats have been proposed; one of the best is to mix two per
cent. of strong sulphuric acid with a quantity of water, in which the
tallow is heated for some time with much stirring; to allow the
materials to cool, to take off the supernatant fat, and re-melt it with
abundance of hot water. More tallow will thus be obtained, and that
considerably whiter and harder than is usually procured by the melters.
I have found that chlorine, and chloride of lime do not improve, but
rather deteriorate the appearance of oils and other fatty bodies.
According to Appert, minced suet subjected to the action of
high-pressure steam in a digester, at 250° or 260° F., becomes so hard
as to be sonorous when struck, whiter, and capable when made into
candles, of giving a superior light. A convenient mode of _rendering_
minced tallow, or melting it, is to put it in a tub, and drive steam
through it from numerous orifices in ramifying pipes placed near the
bottom. Mr. Watt assures me that his plan of purifying fats, patented in
March 1836, has been quite successful. He employs dilute sulphuric acid,
to which he adds a little nitric acid, with a very small quantity of
bichromate of potash, “to supply oxygen;” and some oxalic acid. These
are mixed with the fat in the steaming tub. When the lumps of it are
nearly dissolved, he takes for every ton of fat, one pound of strong
nitric acid, diluted with one quart of water; to which he adds two
ounces of alcohol, naphta, sulphuric ether, or spirits of turpentine;
and after introducing this mixture, he continues the boiling for half an
hour. The fat is finally washed.--As I do not comprehend the _modus
operandi_ of these ingredients, I shall abstain from any comment upon
the recipe.
Others have proposed to use vegetable or animal charcoal first,
especially for rancid oils, then to heat them with a solution of
sulphate of copper and common salt, which is supposed to precipitate the
fetid albuminous matter. Milk of lime has been also prescribed; but it
is I believe always detrimental.
Davidson treats whale oil with infusion of tan, in order to separate the
gelatine and albumine in flocks; next with water and chloride of lime,
to destroy the smell; and lastly, with dilute sulphuric acid, to
precipitate all the lime in the state of a sulphate. This is certainly
one of the cheapest and most effective methods of purifying that
substance.
Braconnot and Raspail have shown that solid animal fats are composed of
very small, microscopic, partly polygonal, partly reniform particles,
which are connected together by very thin membranes. These may be
ruptured by mechanical means, then separated by triturating the fresh
fats with cold water, and passing the unctuous matter through a sieve.
The particles float in the water, but eventually collect in a white
granular crystalline appearance, like starch. Each of them consists of a
vesicular integument, of the nature of stearine, and an interior fluid
like elaine, which afterwards exudes. The granules float in the water,
but subside in spirits of wine. When digested in strong alcohol, the
liquid part dissolves, but the solid remains. These particles differ in
shape and size, as obtained from different animals; those of the calf,
ox, sheep, are polygonal, from 1/50 to 1/350 of an inch in diameter;
those of the sow are kidney-shaped, and from 1/50 to 1/100; those of man
are polygonal, and from 1/50 to 1/600; those of insects are spherical,
and at most 1/500 of an inch.
Fats all melt at a temperature much under 212° F. When strongly heated
with contact of air, they diffuse white pungent fumes, then blacken, and
take fire. When subjected to distillation, they afford a changed fluid
oil, carburetted hydrogen, and the other products of oily bodies.
Exposed for a certain time to the atmosphere, they become rancid, and
generate the same fat acids as they do by saponification. In their fresh
state they are all composed principally of stearine, margarine, and
oleine, with a little colouring and odorous matter; and, in some
species, hircine, from the goat; phocenine, from the dolphin; and
butyrine, from butter. By subjecting them to a great degree of cold, and
compressing them between folds of blotting paper, a residuum is
obtained, consisting chiefly of stearine and margarine; the latter of
which may be dissolved out by oil of turpentine.
_Beef and Mutton Suet._--When fresh, this is an insipid, nearly
inodorous fat, of a firm consistence, almost insoluble in alcohol,
entirely so if taken from the kidneys and mesenteric web of the ox, the
sheep, the goat, and the stag. It varies in its whiteness, consistence,
and combustibility, with the species and health of the animals. That of
the sheep is very white, and very solid. They may all be purified in the
manner above described. Strong sulphuric acid develops readily the acid
fats by stirring it through melted suet. Alkalis, by saponification,
give rise at once to the three acids,--the stearic, margaric, and oleic.
Beef suet consists of stearine, margarine, and oleine; mutton and goat
suet contain a little hircine. The specific gravity of the tallow, of
which common candles are made is, by my experiments, 0·936. The melting
point of suet is from 98° to 104° F. The proportion of solid and fluid
fat in it is somewhat variable, but the former is in much larger
proportion. Mutton suet is soluble in 44 parts of boiling alcohol, of
0·820; beef suet in 44 parts. Marrow fat consists of 76 of stearine, and
24 of oleine; it melts at 115° F.
_Hog’s-lard_ is soft, fusible at 81° F., convertible, by an alkaline
solution, into a stearate, margarate, oleate, and glycerine. Its sp.
grav. is 0·938, at 50° F; It consists of 62 of oleine, and 38 of
stearine, in 100 parts.
_Goose-fat_, consists of 68 oleine and 32 stearine.
_Butter_, in summer, consists of 60 of oleine and 40 of stearine; in
winter, of 35 of oleine, and 65 of stearine; the former substance being
yellow and the latter white. It differs, however, as produced from the
milk of different cows, and also according to their pasture.
The ultimate constituents of stearine, according to Chevreul are, 79
carbon; 11·7 hydrogen; and 9·3 oxygen, in 100 parts.
1,294,009 cwts. of the tallow imported in 1837, were retained for
internal consumption. See MARGARINE, OLEINE, SOAP, STEARINE.
FAULTS (_Failles_, Fr.); in mining, are disturbances of the strata which
interrupt the miner’s operations, and put him at _fault_, to discover
where the vein of ore or bed of coal has been thrown by the convulsions
of nature. Many examples of faults are exhibited under PITCOAL.
FEATHERS (_Plumes_, Fr.; _Federn_, Germ.), constitute the subject of the
manufacture of the _Plumassier_, a name given by the French (and also
the English) to the artisan who prepares the feathers of certain birds
for ornaments to the toilette of ladies and for military men, and to him
also who combines the feathers in various forms. We shall content
ourselves with describing the method of preparing ostrich feathers, as
most others are prepared in the same way.
Several qualities are distinguished in the feathers of the ostrich;
those of the male, in particular, are whiter and more beautiful. Those
upon the back and above the wings are preferred; next, those of the
wings, and lastly, of the tail. The down is merely the feathers of the
other parts of the body, which vary in length from 4 to 14 inches. This
down is black in the males, and gray in the females. The finest white
feathers of the female have always their ends a little grayish, which
lessens their lustre, and lowers their price. These feathers are
imported from Algiers, Tunis, Alexandria, Madagascar, and Senegal; this
being the order of their value.
The _scouring process_ is thus performed:--4 ounces of white soap, cut
small, are dissolved in 4 pounds of water, moderately hot, in a large
basin; and the solution is made into a lather by beating with rods. Two
bundles of the feathers, tied with packthread, are then introduced, and
are rubbed well with the hands for five or six minutes. After this
soaping they are washed in clear water, as hot as the hand can bear.
The whitening or bleaching is performed by three successive operations.
1. They are immersed in hot water mixed with Spanish white, and well
agitated in it; after which they are washed in three waters in
succession.
2. The feathers are azured in cold water containing a little indigo tied
up in a fine cloth. They should be passed quickly through this bath.
3. They are sulphured in the same way as straw hats are (see
SULPHURING); they are then dried by hanging upon cords, when they must
be well shaken from time to time to open the fibres.
The ribs are scraped with a bit of glass cut circularly, in order to
render them very pliant. By drawing the edge of a blunt knife over the
filaments they assume the curly form so much admired. The hairs of a
dingy colour are dyed black. For 20 pounds of feathers, a strong
decoction is made of 25 pounds of logwood in a proper quantity of water.
After boiling it for 6 hours, the wood is taken out, 3 pounds of
copperas are thrown in; and, after continuing the ebullition for 15 or
20 minutes, the copper is taken from the fire. The feathers are then
immersed by handfuls, thoroughly soaked, and worked about; and left in
for two or three days. They are next cleansed in a very weak alkaline
lye, and soaped three several times. When they feel very soft to the
touch, they must be rinsed in cold water, and afterwards dried. White
feathers are very difficult to dye a beautiful black. The acetate of
iron is said to answer better than the sulphate, as a mordant.
For dyeing other colours, the feathers should be previously well
bleached by the action of the sun and the dew; the end of the tube being
cut sharp like a toothpick, and the feathers being planted singly in the
grass. After fifteen days’ exposure, they are cleared with soap as above
described.
_Rose colour_ or _pink_, is given with safflower and lemon juice.
_Deep red_, by a boiling hot bath of Brazil wood, after aluming.
_Crimson._ The above deep red feathers are passed through a bath of
cudbear.
_Prune de Monsieur._ The deep red is passed through an alkaline bath.
_Blues of every shade_, are dyed with the indigo vat.
_Yellow_; after aluming, with a bath of turmeric or weld.
Other tints may be obtained by a mixture of the above dyes.
Feathers have some more useful employments than the decoration of the
heads of women and soldiers. In one case, they supply us with a soft
elastic down on which we can repose our wearied frames, and enjoy sweet
slumbers. Such are called _bed_ feathers. Others are employed for
writing, and these are called _quills_.
Goose feathers are most esteemed for beds, and they are best when
plucked from the living bird, which is done thrice a year, in spring,
midsummer, and the beginning of harvest. The qualities sought for in bed
feathers, are softness, elasticity, lightness, and warmth. Their only
preparation when cleanly gathered are a slight beating to clear away the
loose matter, but for this purpose they must be first well dried either
by the sun or a stove. Bleaching with lime water is a bad thing, as they
can never be freed from white dust afterwards.
The feathers of the eider duck, _anas mollissima_, called eider down,
possess in a superior degree all the good qualities of goose down. It is
used only as a covering to beds, and never should be slept upon, as it
thereby loses its elasticity.
_Quills_ for writing. These consist usually of the feathers plucked out
of the wings of geese. Dutch quills have been highly esteemed, as the
Dutch were the first who hit upon the art of preparing them well, by
clearing them both inside and outside from a fatty humour with which
they are naturally impregnated, and which prevents the ink from flowing
freely along the pens made with them. The Dutch for a long time employed
hot cinders or ashes to attain this end; and their secret was preserved
very carefully, but it at length transpired, and the process was then
improved. A bath of very fine sand must be kept constantly at a suitable
temperature, which is about 140° F.; into this, the quill end of the
feather must be plunged, and left in it a few instants. On taking them
out they must be strongly rubbed with a piece of flannel, after which
they are found to be white and transparent. Both carbonate of potash in
solution and dilute sulphuric acid have been tried to effect the same
end, but without success. The yellow tint which gives quills the air of
age, is produced by dipping them for a little in dilute muriatic acid,
and then making them perfectly dry. But this process must be preceded by
the sand-bath operation. The above is the French process.
Quills are dressed by the London dealers in two ways; by the one, they
remain of their natural colour; by the other, they acquire a yellow
tint. The former is called the Dutch method, and the principal workman
is called a Dutcher. He sits before a small stove fire, into which he
thrusts the barrel of the quill for about a second, then lays its root
quickly below his blunt-edged knife called a hook, and, pressing this
firmly with the left hand, draws the quill briskly through with his
right. The bed on which the quill is laid to receive this pressure is
called the plate. It is a rectangular smooth lump of iron, about 3
inches long, 1-1/2 broad, and 2-1/2 thick, which is heated on his stove
to about the 350th degree Fahr. The hook is a ruler of about 15 inches
in length, somewhat like the patten-makers’ knife, its fulcrum being
formed at the one end by a hook and staple, and the power of pressure
being applied by the hand at the other end. The quill, rendered soft and
elastic by the heat, endures the strong scraping action of the tool, and
thus gets stripped of its opaque outer membrane, without hazard of being
split. A skilful workman can pass 2000 quills through his hands in a day
of 10 hours.
They are next cleaned by being scrubbed by a woman with a piece of rough
dog-fish skin, and finally tied up by a man in one quarter of hundred
bundles.
In another mode of dressing quills, they are steeped a night in
decoction of turmeric, to stain them yellow; taken out and dried in warm
sand contained in a pot, then scraped by the Dutcher as above described.
The first are reckoned to make the best pens, though the second may
appear more beautiful.
Crow quills for draughtsmen, as well as swan quills, are prepared in the
same way. The quills plucked from well-fed living birds have most
elasticity, and are least subject to be moth-eaten. The best are those
plucked, or which are spontaneously cast in the month of May or June,
because they are then fully ripe. In the goose’s wing the five exterior
feathers only are valuable for writing. The first is the hardest and
roundest of all, but the shortest. The next two are the best of the
five. They are sorted into those of the right and the left wing, which
are differently bent. The heaviest quills are, generally speaking, the
best. Lately, steaming for four hours has been proposed as a good
preparation.
FECULA (_Fecule_, Fr.; _Stärkemehl_, Germ.); sometimes signifies corn
flour, sometimes starch from whatever source obtained.
FELSPAR (_Orthose_, Fr.; _Feldspath_, Germ.) is a mineral crystallizing
in oblique rhomboidal prisms, susceptible of two cleavages; lustre more
pearly than vitreous; spec. grav. 2·39 to 2·58; scratches glass; yields
no water when calcined; fusible at the blowpipe into a white enamel; not
affected by acids. The liquid left from its analytical treatment with
nitrate of baryta, nitric acid, and carbonate of ammonia, affords on
evaporation an alkaline residuum which precipitates platina from its
chloride, and appears from this, as well as other tests, to be potash.
Felspar consists of--silica, 66·75; alumina, 17·50; potash, 12; lime,
1·25; oxide of iron, 0·75. _Rose._ This mineral is a leading constituent
of granite; and in its decomposed state furnishes the petuntse or
Cornish stone, so much used in the porcelain and best pottery
manufactures.
FELTING; (_Feutrage_, Fr.; _Filzen_, Germ.) is the process by which
loose flocks of wool, and hairs of various animals, as the beaver,
rabbit, hare, &c., are mutually interlaced into a compact textile
fabric. The first step towards making felt is to mix, in the proper
proportions, the different kinds of fibres intended to form the stuff;
and then, by the vibratory strokes of the bowstring, to toss them up in
the air, and to cause them to fall as irregularly as possible, upon the
table, opened, spread, and scattered. The workman covers this layer of
loose flocks with a piece of thick blanket stuff slightly moistened; he
presses it with his hands, moving the hairs backwards and forwards in
all directions. Thus the different fibres get interlaced, by their ends
pursuing ever tortuous paths; their vermicular motion being always,
however, root foremost. As the matting gets denser, the hand pressure
should be increased in order to overcome the increasing resistance to
the decussation.
A first thin sheet of soft spongy felt being now formed, a second is
condensed upon it in like manner, and then a third, till the requisite
strength and thickness be obtained. These different pieces are
successively brought together, disposed in a way suitable to the
wished-for article, and united by continued dexterous pressure. The
stuff must be next subjected to the fulling mill. See HAT MANUFACTURE.
FERMENT (Eng. and Fr.; _Hefe_, Germ.) is the substance which, when added
in a small quantity to vegetable or animal fluids, tends to excite those
intestine motions and changes which accompany fermentation. It seems to
be the result of an alteration which vegetable albumen and gluten
undergo with contact of air amidst a fermenting mass. The precipitate or
lees which fall down when fermentation is finished consist of a mixture
of the fermenting principle with the insoluble matters contained in the
fermented liquor, some of which, like hordeine, existed in the worts,
and others are probably generated at the time.
To prepare a pure ferment, or at least a compound rich in that
principle, the precipitate separated during the fermentation of a clear
infusion of malt, commonly called yeast or barm, is made use of. This
pasty matter must be washed in cold distilled water, drained and
squeezed between the folds of blotting paper. By this treatment it
becomes a pulverulent mass, composed of small transparent grains,
yellowish gray when viewed in the compound microscope. It contains much
water, and is therefore soft, like moist gluten and albumen. When dried,
it becomes like these bodies, translucid, yellowish brown, horny, hard,
and brittle. In the soft humid state it is insipid, inodorous, insoluble
in water and alcohol. If, in this state, the _ferment_ be left to itself
at a temperature of from 60° to 70° F., but not in too dry a situation,
it putrefies with the same phenomena as vegetable gluten and albumen,
and leaves, like them, a residuum resembling old cheese.
At the beginning of this change, particularly if the ferment be enclosed
in a limited portion of air, there is an absorption of oxygen gas with a
fivefold disengagement of carbonic acid gas; while acetic acid makes its
appearance in the substance. When distilled by itself it affords the
same products as gluten. Dilute acids dissolve it very readily; and so
does potash with the production of ammonia, a peculiar circumstance, for
in dissolving gluten the alkali causes no such evolution.
The property possessed by yeast of determining the fermentation of a
properly diluted solution of sugar is very fleeting, and is lost by very
trifling alterations. It is destroyed by complete desiccation, and
cannot be restored by moistening it again. The attempts made in London
to squeeze out the liquid part of yeast in bags placed in a powerful
press, and to obtain a solid cake, in order to transport ferment to
India, have had but a very partial success; for its virtue is so
impaired that it will rarely excite a perfect fermentation in the best
prepared worts. The same method is adopted in Germany, to send yeast to
only moderate distances; and therefore with more advantage.
If yeast be boiled for ten minutes, it loses the greater part of its
fermenting power, and by longer boiling it becomes inert.
When alcohol is poured upon yeast, it immediately destroys its
fermenting faculties, though, on filtering it off, it seems to carry no
remarkable principle with it. One thousandth part of sulphuric acid
equally deprives yeast of its peculiar property, and so does a little
strong acetic acid. All the acids and the salts, especially those which
part readily with their oxygen, produce the same effect. A very small
quantity of sulphurous acid, or sulphites, mustard powder, particularly
the volatile oil of mustard, and in general the volatile oils that
contain sulphur, as well as the vegetables which yield them, such as
horse-radish and garlick, all kill the fermenting agent. Lastly,
fermentation is completely stopped by a moderate depression of
temperature.
During fermentation the yeast undergoes a change; it loses the property
of causing another wort to ferment. This change probably depends upon
the chemical reaction between the ferment and the sugar that is
decomposed; for a certain quantity of yeast can effect the fermentation
of only a certain quantity of sugar, and all the sugar exceeding this
quantity remains unaltered in the liquor. It has been concluded from
some rather loose experiments, that one part and a half of yeast
(supposed to be in the dry state), is adequate to the fermentation of a
solution of 100 parts of pure sugar. When such a solution is fermented
by the precise proportion of yeast, the fermenting principle is
exhausted, for no new yeast is formed in it. There is a deposit indeed
to about half the weight of the yeast employed, of a white matter
insoluble in water, which affords no ammonia by dry distillation, and is
incapable of acting as a ferment upon a fresh saccharine solution.
Of all the bodies convertible into yeast during fermentation, vegetable
gluten and albumen possess the most rapid and energetic powers. But
ordinary glue, isinglass, animal fibrine, curd or _caseum_, albumine,
urine and other azotized substances, all enjoy the property of causing
a solution of sugar to ferment; with this difference, that whilst yeast
can establish a complete fermentation in less than an hour, at a
temperature of about 68°, the above substances require several days,
with a heat of from 77° to 87° F., for becoming ferments, and for
occasioning fermentation. Substances devoid of nitrogen do not produce a
ferment.
FERMENTATION. (Eng. and Fr.; _Gährung_, Germ.) When organic substances,
under the influence of water, air, and warmth, are abandoned to the
reciprocal operation of their proximate principles, (sugar, starch,
gluten, &c.), they are entirely changed and decomposed, so that their
ultimate principles (oxygen, hydrogen, carbon, and in some cases azote,)
combine in new proportions, and thus give birth to various new
compounds. To this process, the general name of fermentation has been
given. These operations and their products differ according to the
differences of the substances, and of the circumstances in which they
are placed. The following may be enumerated as sufficiently distinct
species of fermentation. 1. The _saccharine_ fermentation, in which
starch and gum are changed into sugar. 2. The _vinous_ fermentation, in
which sugar is converted into alcohol. 3. The _mucilaginous_
fermentation, in which sugar is converted into slime, instead of
alcohol. 4. The _acetous_ fermentation, in which alcohol and other
substances are converted into vinegar. 5. The _putrid_ fermentation or
putrefaction, which characterizes particularly the decomposition of
azotized organic substances.
1. _The saccharine fermentation._ When a paste made by boiling one part
of starch with twelve parts of water is left entirely to itself, water
merely being stirred in as it evaporates, at the end of a month or two
in summer weather it is changed into sugar, equal in weight to from one
third to one half of the starch, and into gum, equal to from one fifth
to one tenth, with a residuum of starch paste somewhat altered. This
saccharifying process advances much quicker through the co-operation of
vegetable albumine or gluten, acting as a ferment. If we boil two parts
of potato starch into a paste with twenty parts of water, mix this paste
with one part of the gluten of wheat flour, and set the mixture for 8
hours in a temperature of from 122° to 167° F., the mixture soon loses
its pasty character, and becomes by degrees limpid, transparent and
sweet, passing at the same time first into gum, and then into sugar. The
remainder consists of the unchanged starch with the altered gluten,
which has become sour, and has lost the faculty of acting upon fresh
portions of starch. It is probable, however, that the sugar formation in
the first case, when the starch undergoes a spontaneous change, may be
due to the action of a small portion of gluten and albumine left in the
starch, since a putrefactive smell is eventually evolved indicative of
that azotized matter. The gum into which during this process the starch
is first converted, and which becomes afterwards sugar, is of the same
nature as British gum, formed by the roasting of starch.
This production of sugar takes place in the germination and kiln-drying
of malt; and the mashing of the brewer as well as the sweetening of
bread in baking, rests upon the same principles. In many cases the
vinous fermentation precedes the saccharification, or accompanies it;
the starchy parts of the fermenting mass changing into sugar, while the
previously formed sugar becomes wine or beer. In the sweetening of
fruits by keeping, a similar process occurs; the gummy and starchy
fibres become sugar from the action of the glutinous ferment which they
contain; as happens also to the juices of many fruits which sweeten for
a little while after they have been expressed.
The nature of this sugar formation through the influence of gluten upon
starch, is undoubtedly the same as the conversion of starch into sugar,
by boiling it with sulphuric acid; though the whole theory of this
change is not entirely developed.
The most energetic substance for the conversion of starch into sugar, is
the malt of barley. According to the researches of Payen and Persoz, the
gum which by this process is first formed, may be prevented from going
into sugar, by merely exposing it to a boiling heat, and hence we have
it in our power either to make sugar or gum at pleasure. Of finely
ground malt from 10 to 25 parts must be taken for 100 parts of starch.
Into a pan placed in a water bath, 400 parts of water being warmed to
from 77° to 86° F., the ground malt must be stirred in, and the
temperature must be raised to 140°. The 100 parts of starch must now be
added, and well mixed. The heat is then to be increased to 158°F.; and
be so regulated that it shall not fall below 149°, nor rise above 167°.
In the course of 20 or 30 minutes the originally milky and pasty liquid
will become gradually more attenuated, and eventually it will turn as
fluid nearly as water. This is the point of time in which the starch has
passed into gum, or into the substance lately denominated _dextrine_ by
the chemists. Should this mucilaginous matter, which appears to be a
mixture of gum and a little starchy sugar, be wished for in that state,
the temperature of the liquid must be suddenly raised to the boiling
point, whereby the further action of the malt upon it is stopped. But on
the other hand if sugar be desired, then the temperature must be
steadily maintained at from 158° to 167° for three quarters of an hour,
in which time the greater part of the starch will have become sugar,
and from the evaporation of the fluid a starchy syrup will be obtained,
entirely similar to that procurable by the action of very dilute
sulphuric acid upon starch.
The substance which operates this saccharine change, or the appropriate
yeast of the sugar fermentation, which had been previously imagined to
be a residuum of gluten or vegetable albumen in the germinated grain,
has been traced by Payen and Persoz to a peculiar proximate vegetable
principle called by them _diastase_. This substance is generated during
the germination of barley, oats, and wheat, and may be obtained
separately by infusing the ground malt in a small quantity of cold
water, straining off the liquor, then filtering it, and heating the
clear solution in a water bath to the temperature of 158° F. The greater
part of the vegetable albumen is thus coagulated, and must be separated
by a fresh filtration; the liquid is afterwards treated with alcohol as
long as the flocculent precipitate of diastase falls. In order to purify
it still more completely from the azotized matter, it may be once more
dissolved in water, and again precipitated by alcohol. When dried at a
low temperature, it appears as a white solid, which contains no azote,
is insoluble in strong alcohol, but dissolves in weak alcohol and water.
Its solution is neutral and tasteless; and if left to itself, it changes
spontaneously sooner or later according to the degree of warmth, and
becomes sour. At the temperature of from 149° to 168°, it has the
property of converting starch into gum or dextrine, and sugar; and, when
sufficiently pure, it does this with such energy, that one part of it is
capable of saccharifying 2000 parts of dry starch. It acts the more
rapidly the larger its proportion. Whenever the solution of diastase
with starch or dextrine, has been heated to the boiling point, it loses
the property of transforming these substances. One hundred parts of well
malted barley appear to contain about one part of this new body.
2. _The Vinous Fermentation._--In this fermentation the sugar existing
in watery solution is, by the operation of the ferment or yeast,
converted into alcohol, with disengagement of carbonic acid gas. If we
dissolve one part of pure sugar in ten parts of water, and leave the
solution in a temperature of from 68° to 77° F., which is that most
favourable to fermentation, it will remain unaltered. But if we stir
into that solution some beer yeast, the phenomena of fermentation soon
appear in the above circumstances; for carbonic acid gas is evolved,
with intestine movements of the liquid, and an increase of its
temperature. A body of yeast rises to the surface, and exhibits a
continual formation and rupture of air bubbles. At length the sugar
being in a great measure decomposed, the motions cease, the liquor
becomes clear, and instead of being a syrup, it is now a dilute alcohol.
The yeast has by this time fallen to the bottom in a somewhat compact
form, and of a whitish colour, deprived of the property of exciting
fermentation in fresh syrup, provided no undue excess of it was added at
first, for that alone would remain effective. Experience shows that for
the conversion of a determinate quantity of sugar by fermentation, a
determinate quantity of yeast is necessary, which has been estimated at
about 1-1/2 per cent. in the dry state. When the yeast has been
decomposed by fermenting its definite proportion of sugar, it loses its
fermentable property, and leaves the excess of sugar unaffected, forming
a sweet vinous solution. The same thing happens if the yeast be
separated from the wort by a filter in the progress of the fermentation,
for then all intestine motion speedily stops, although much saccharine
matter remains.
In the juices of sweet fruits, of grapes, for example, the ferment is
intimately associated with the sugar. It is at first soluble and
inactive, till it absorbs oxygen from the atmosphere, whereby it becomes
an operative ferment, but, at the same time, insoluble, so as to
precipitate at the end of the process. When the expressed juice of the
grape, or _must_, is inclosed in a vessel out of contact of air, and
there subjected to the heat of boiling water, the small portion of
oxygen present is rendered inactive, and the liquor experiences no
fermentative change. If the grapes be squeezed in an atmosphere deprived
of oxygen, and confined in the same, the juice will also remain
unaltered. Recently expressed grape juice is limpid, and manifests the
commencement of fermentation by the separation of the yeasty substance,
which can take place only with access of air. The solution becomes
turbid after a certain time, gas begins to be evolved, and the separated
ferment decomposes the sugar. At the end of the process the yeast
collects at the bottom of the vessel, usually in larger quantity than
was sufficient to complete the fermentation; and hence a considerable
portion of it possesses still the fermentative faculty. The fermentation
itself, when once begun, that is, whenever the yeasty particles are
evolved, and float in the liquid, for which evolution a very minute
quantity of oxygen is sufficient, is thenceforth independent of the
contact of air, and goes on as well in close as in open vessels; so that
the production of alcohol and carbonic acid depends solely upon the
mutual reaction of the ferment and the sugar.
The yeast, which may be obtained tolerably pure from a fine infusion of
malt in a state of fermentation, after being washed with cold water to
separate the soluble, gummy, and saccharine matter, and after being
pressed between folds of blotting paper, constitutes a pulverulent,
grayish yellow, granular substance, destitute of both taste and smell,
insoluble both in water and alcohol. Cold water dissolves, indeed, only
1/400, and boiling water very little more.
The essentially operative constituent of yeast is a peculiar azotized
matter, which in the wine vat is mixed with some tartar and other salts,
and in the beer tun with gum, starch, &c. This animalized substance may
be obtained in a separate state, according to Braconnot, by acting upon
the washed yeast powder with a weak lye of carbonate of potash, and by
decomposing the solution with vinegar, whereby the matter is thrown down
in a gelatinous form. The substance thus obtained is insoluble in cold
water and alcohol, but dissolves readily in very dilute alkaline lyes,
and even in lime water. When diffused through water, it assumes a
homogeneous aspect, as if it were really dissolved; but when this
mixture is heated, the animalized matter coagulates, and separates in
thick flocks. In this state it has lost its former properties, being no
longer soluble in alkaline lyes, even when concentrated. Acids exercise
no solvent power over this peculiar matter; they precipitate it from its
solutions, as do also the earthy and metallic salts, which, moreover,
combine with it. This is also the case with tannin. The combination of
the ferment stuff with acids increases the stability of its
constitution, and counteracts its tendency to influence solutions of
sugar. These properties of the operative principle of yeast explain many
of the phenomena of fermentation, as we shall presently see.
The animalized matter of yeast resembles gluten, albumen, caseum, and
other azotized substances; if any one of these be put into a saccharine
solution ready for fermentation, it will begin to operate a change, when
aided by warmth and time, if it be previously decomposed in some measure
to facilitate its influence; or if these substances be brought into a
slightly putrescent state beforehand, they will cause more speedy
fermentation. Thus white of egg, when added to saccharine liquors,
requires a period of three weeks, with a temperature of 96° F., before
it will excite fermentation; afterwards the excess of the albumen forms
a precipitate which may be used instead of yeast upon other sweet worts.
The rapidity with which such azotized substances are capable of being
converted into ferments of more or less purity and power is very
variable; vegetable gluten and albumen being best fitted for this
purpose. This conversion is accelerated when the sweet liquor in which
the substance is diffused or dissolved has already begun to ferment;
whence it appears that the presence of carbonic acid gas, combined with
the liquor, is here of singular influence. Upon it, in fact, the
formation and elimination of the yeast in fermenting liquors depend.
A solution of pure sugar, which has been made to ferment by the addition
of yeast, furnishes no new yeast; but there remains after the process a
portion of the yeast originally mixed, in an altered inoperative
condition, should its quantity have been exactly adequate to the
decomposition of the sugar, or in an operative state, should the
quantity have been originally excessive.
But if the fermentable liquor contains vegetable albumen and gluten, as
is commonly the case with the sweet juices of fruits and beer worts,
these substances become changed into ferments in the course of the
fermentation induced by the yeast, and, being superfluous, so to speak,
for that particular process, they remain entire at the end, and may be
collected for use in other operations.
Upon this principle is founded the increased production of yeast, and
the manufacture of what has been called _artificial barm_, in which the
fermentation is conducted chiefly with a view to the formation of yeast.
To the fermenting mass, those kinds of meal are added which abound in
albumen and gluten, as barley, beans, or wheat, for instance; and the
process is similar to the production of a great lump of leaven, from the
action of a small piece of it upon dough. The following prescription
will illustrate this subject. Take three ounces of bean flour, add to it
five quarts of boiling water, and boil the mixture for half an hour.
Pour the decoction into a vessel, and stir into it, while hot, 56 ounces
of wheaten flour. After the mixture cools to the temperature of 54° F.,
add to it about two quarts of beer barm, stirring the whole well
together. About 24 hours after the commencement of the fermentation,
incorporate with the mixture 112 ounces of barley or bean flour, till it
becomes a uniform dough, which must be thoroughly kneaded, rolled out
into cakes about an inch thick, and cut into pieces of the size of a
dollar. These cakelets must be dried upon laths in the sun in favourable
weather, and then put up in a dry situation. For use, one of these discs
is to be broken into pieces, laid in warm water, and set in a warm place
during 12 hours. The soft mass will then serve the purpose of beer
yeast.
Or we may mix equal parts of barley malt, wheat malt, and crushed rye,
pour water at the temperature of 122° F. over them into a tub till it
stand a span above their surface; then stir well together, and allow the
whole to remain at rest for a few hours, till it cools to about 65° F.
We must now add for each pound of the mingled meals, a quarter of an
ounce of beer barm. The tub must be then covered, and preserved at a
temperature of 63° F. The husks, as they begin to rise to the surface,
in consequence of the fermentation, must be taken off, and squeezed
through a cloth over the vessel. When the meal comes afterwards to
subside to the bottom, the whole must be strained through a canvas bag,
and freed from the superfluous moisture by squeezing. The bag with its
doughy mass must next be surrounded with dry ashes, to remove the
remaining humidity, and to arrest any further fermentation. This
consistent ferment may be used instead of beer yeast.
It is difficult to prepare an artificial yeast without barm. The best
process for this purpose is the following. Take five parts of honey, one
part of powdered tartar, and sixteen parts of wheat or barley malt, stir
the whole in water of the temperature of 122° F., and place in a
fermenting heat; when the yeast will, as usual, be eliminated.
The change which gluten or vegetable albumen undergoes in the different
kinds of meal, when it becomes a ferment, consists apparently in an
oxidation, since analysis shows that this ferment contains more oxygen
than gluten does.
It has been already stated that yeast in its liquid condition readily
putrefies, and becomes altogether useless for the process of
fermentation. In order to preserve it for some time, it must be dried to
such a degree as to resist spontaneous decomposition without losing its
fermentative faculty; but completely dried yeast loses that property,
and does not recover it by being again moistened. Beer barm may be dried
after being washed several times with cold water, till the last quantity
comes off clear; but the insoluble portion must be allowed to settle
fully before the water is poured away from it. The residuum being freed
as much as possible from water, by drainage and pressure between flannel
cloths, is to be dried in the shade by a current of warm air as quickly
as possible, with the aid of frequent turning over. It must be
afterwards kept in dry earthen vessels. Yeast may also be preserved a
short time in activity by being kneaded with as much barley or wheat
flour as it can take up without losing the doughy consistence. Dried
yeast has, however, always an impaired activity. The easiest and most
certain method of preserving yeast in its primitive power, is by mixing
it, after pressure in flannel, with as much pulverized sugar as will
render it dry, and putting up the mixture in air-tight vessels. The
fermentative power of yeast is destroyed by the following means: 1. as
already stated, by making it completely dry either by the evaporation of
the water, or its abstraction by alcohol; 2. by boiling, which if
continued for ten minutes renders yeast quite inoperative; 3. by the
action of such substances as dissolve out its essential constituents; by
alkalis, for instance, since the particles of yeast seem to be operative
only in their insoluble granular state; 4. by such substances as form
combinations with it, and thereby either alter its nature, or at least
increase the cohesion of its constituent parts, so that they can no
longer operate upon sweet liquors by the decomposing affinity of its
ultimate particles. Such bodies are the acids, especially the mineral
ones, tannin and most salts, particularly the metallic, which unite with
the yeast into new compounds. The volatile oils which contain sulphur
exercise the same paralyzing influence upon yeast.
The circumstances which promote, and are necessary to, the vinous
fermentation are, conformably to the above views, the following:--1. The
presence of the proper quantity of active yeast, and its proper
distribution through the worts. If in the course of a slack fermentation
the yeast subsides to the bottom, the intestine motions cease entirely,
but they may be excited anew by stirring up the ingredients, or rousing
the tun, as the brewers say. 2. A certain degree of warmth, which should
never be less than 51° F., nor more than 86°; the temperature of from
68° to 77° being the most propitious for the commencement and progress
of fermentation. When other circumstances are the same, the rapidity of
the fermentation is proportional to the temperature within certain
limits, so that by lowering it, the action may be moderated at pleasure.
3. The fermentation proceeds the better and more equably the greater the
mass of fermenting liquor, probably on account of the uniformly high
temperature, as well as the uniform distribution of the active particles
of the yeast by the greater energy of the intestine movements. 4. The
saccharine solution must be sufficiently diluted with water; when too
much concentrated it will not ferment. Hence very sweet musts furnish
wines containing much undecomposed sugar. For a complete fermentative
action, one part of sugar should be dissolved in ten parts of water.
Fermentation maybe tempered or stopped: 1. by those means which render
the yeast inoperative, particularly by the oils that contain sulphur, as
oil of mustard; as also by the sulphurous and sulphuric acids. The
operation of the sulphurous acid in obstructing the fermentation of must
consists partly, no doubt, in its absorbing oxygen, whereby the
elimination of the yeasty particles is prevented. The sulphurous acid,
moreover, acts more powerfully upon fermenting liquors that contain
tartar, as grape juice, than sulphuric acid. This acid decomposes the
tartaric salts, and, combining with their bases, sets the vegetable acid
free, which does not interfere with the fermentation; but the sulphurous
acid operates directly upon the yeast: 2. by the separation of the
yeast, either with the filter or by subsidence: 3. by lowering the
temperature to 45° F. If the fermenting mass become clear at this
temperature, and be drawn off from the subsided yeast, it will not
ferment again, though it should be heated to the proper pitch.
The products of vinous fermentation are carbonic acid gas, and alcohol;
of which the former escapes during the process, except in the case of
the sparkling wines, like champaign, that are partially fermented in
close vessels. The alcohol remains in the fermented liquor. 100 parts of
sugar afford by complete decomposition nearly 50 parts of alcohol.
According to Thenard, 100 parts of sugar are converted into 46·8 parts
of carbonic acid, and 49·38 of alcohol; besides 3·82 parts of carbon
otherwise employed, which the sugar contained, above what is present in
the former two products. This chemist found in the fermented liquor 4
per cent. of an extractive matter, soluble in water, and having an
acidulous reaction, to whose formation, probably, that excess of carbon
may be necessary. In what way the action of the yeasty particles upon
the saccharine substance is carried on in the vinous fermentation, or
what may be the interior working of this process, is not accurately
understood. The quantitative relation of the carbonic acid and alcohol
to the sugar is pretty well made out; but the determination of the
ultimate principles of the ferment itself, before and after the vinous
change, and of the residuum dissolved in the fermented liquor, has not
been well ascertained. It is probable that the yeast undergoes in the
process a similar decomposition to that of the putrefactive, and that
its elementary constituents enter into new combinations, and abstract so
much carbon and hydrogen from the sugar, that the remainder, amounting
to 96 per cent. of the whole, may constitute one atom of alcohol and one
of carbonic acid.
3. _The slimy or glutinous fermentation._--This process takes place in
weak solutions of sugar, at ordinary fermenting temperatures, where,
from defect of good yeast, the vinous fermentation cannot proceed. In
such circumstances from one part of sugar, one third part of gum is
formed. According to Desfosses however, 100 parts of sugar afford 109·48
of gum or slime. This is formed when one part of sugar is dissolved in
twenty parts of water, which had been previously boiled with washed barm
or gluten, and then filtered. The process proceeds slowly and quietly,
equally well in close vessels, as with contact of air, and continues at
ordinary temperatures about 12 days; but it goes on more rapidly and
completely at the heat of from 77° to 86° F. A small quantity of
hydrogen and carbonic acid gas is disengaged, in the proportion of two
to one by volume. The fermented liquor becomes turbid, and assumes a
tough thready appearance, like a decoction of linseed. A small addition
of sulphuric or sulphurous acid, of muriatic acid and alum, or of
tannin, impedes this species of fermentation; because these substances
combine, as in the vinous fermentation, with the ferment into an
insoluble precipitate, unsusceptible of further change. In many wines,
especially when bottled, this slimy fermentation occurs, and occasions
their ropiness, which may be best remedied or prevented by the addition
of as much tannin as will precipitate the dissolved mucous matter. This
species of fermentation attacks very rapidly the rinsing waters of the
sugar refiner, which always contain some fermentative gluten. A little
alum is the best preventative in this case, because it precipitates the
dissolved ferment.
4. _The acetous or sour fermentation._--In this process, alcohol, more
or less dilute, is resolved into water and vinegar, in consequence of
the operation of the ferment; oxidizement of the alcohol being effected
by the oxygen of the atmospherical air. The requisites of this process
have been already detailed under the article ACETIC ACID. They are the
presence of atmospherical air; alcohol diluted to a certain degree with
water ferment or yeast, and a temperature above 66° F. The most active
ferments are such substances as have already passed into the acetous
state; hence vinegar, especially when it contains some yeasty particles,
or is combined with porous and spongy bodies, so as to multiply its
points of contact with the vinous liquor, is particularly powerful.
Common yeast may also be employed for vinegar ferments, if it be imbued
with a little vinegar, with leaven, crusts of bread soaked in vinegar,
the stalks and husks of grapes, sawdust and shavings of beech or oak
impregnated with vinegar, or the slimy sediment of vinegar casks called
_mother_; all of which operate as ferments chiefly in consequence of the
vinegar which they contain. The inside shavings of the staves of vinegar
tuns act on the same principle.
The acetous fermentation may, moreover, go on along with the vinous in
the same liquor, when this contains sugar as well as alcohol. Whilst the
acidification of the alcohol is effected by the absorption of oxygen
from the atmosphere, the sugar becomes alcohol with disengagement of
carbonic acid, and then passes into vinegar. Since most liquors intended
for making vinegar, such as wine, juices of fruits, ales, &c., contain
still a little sugar, they disengage always a little carbonic acid.
Besides spirits, some other substances, such as gum, the mucilage of
plants, and starch paste, directly ferment into vinegar. Sugar also
seems to be convertible into vinegar without any vinous change. The
albuminous matter of potato juice, precipitated by vinegar, serves as a
proper ferment for that purpose, when added in its moist state to weak
syrup. 5. See PUTREFACTION.
Mr. William Black, in his treatise on Brewing, has, with much ingenuity
and apparent truth, endeavoured to show that the process of fermentation
is strongly influenced by electricity, not only that of the atmosphere,
as has been long known from the circumstance of beer and wine becoming
speedily sour after thunderstorms, but the voltaic, produced by electric
combinations of metals in the fermenting tuns. He therefore recommends
these tuns to be made with as little metallic work as possible, and to
be insulated from the floor of the brewhouse. For the propriety of this
advice he adduces some striking examples. Wort which had become
stationary in its fermentation, on being pumped out of square gyles
imbedded in the floor, into casks placed upon wooden stillions, began
immediately to work very well, and gained about 6 degrees of attenuation
while throwing off its yeast. From the stagnation of the process in the
gyles, he had in the morning predicted an approaching thunderstorm,
which accordingly supervened in the course of the evening. In further
support of his views he instances the fact, that, in dairies where the
milk is put into porcelain vessels, and placed upon wooden shelves, it
is seldom injured by lightning; but when contained in wooden or leaden
vessels, and placed upon the ground, it almost invariably turns sour in
thundery weather. His general conclusion is “that the preservation or
destruction of beer depends upon electricity; and the most certain mode
of preservation is to insulate as much as possible, both the squares and
all other utensils or vessels connected with the brewing or storing of
beer.”
Mr. Black further considers that unsoundness of worts is often the
result of electricity excited between the mash tun and the copper.
Why is beer liable to get spoiled in thunder storms, though apparently
well insulated in glass bottles?
I shall conclude this article with Mr. Black’s description of the
phenomena of beer fermentation. In every regular process there are five
distinct stages. In the first we see a substance like cream forming all
round the edges of the gyle tun; which extends towards the centre until
the whole is creamed over, constituting the first change. Next a fine
curl appears like cauliflower, which also spreads over the square
surface, and according to the strength and appearance of this curl, the
quality of the fermentation may be predicated. This he calls the second
stage. What is technically called the _stomach_ or vinous vapour now
begins to be smelt, and continues to gain strength till the process is
concluded. From the vinous energy of this odour, and the progressive
attenuation of the wort, the vigour of the fermentation may be inferred.
The experienced brewer is much guided in his operations by the
peculiarity of this effluvium. The third change is when the cauliflower
or curling top rises to a fine rocky or light yeasty head; and when this
falls down, the fourth stage has arrived. Finally the head should rise
to what is called close yeasty, having the appearance of yeast all over.
About this period the gas becomes so powerful as to puff up occasionally
in little bells or bladders about the size of a walnut, which
immediately break. The bells should appear bright and clear. If they be
opaque or whey coloured, there is some unsoundness in the wort. The
great point is to add just so much yeast as to carry the fermentation
completely through these five changes at the regular periods.
FERROCYANATE, or, more correctly, FERROCYANIDE. (_Ferrocyanure_, Fr.;
_Eisencyanid_, Germ.) Several compounds of cyanogen and metals possess
the property of uniting together into double cyanides; of which there
are none so remarkable in this respect, as the protocyanide of iron.
This appears to be capable of combining with several simple cyanides,
such as that of potassium, sodium, barium, strontium, calcium, and
ammonium. The only one of these double cyanides of any importance in
manufactures is the first, which is described under its commercial name,
PRUSSIATE OF POTASH.
FERROPRUSSIATES; another name for Ferrocyanides.
FIBRE, VEGETABLE, called also LIGNINE; (_Ligneux_, Fr.;
_Pflanzen-faserstoff_, Germ.) is the most abundant and general
ingredient of plants, existing in all their parts, the root, the leaves,
the stem, the flowers, and the fruit; amounting in the compact wood to
97 or 98 per cent. It is obtained in a pure state by treating saw-dust
successively with hot alcohol, water, dilute muriatic acid, and weak
potash lye, which dissolve, first, the resinous; second, the extractive,
and saline matters; third, the carbonate and phosphate of lime; and,
lastly, any residuary substances. Ligneous fibres, such as saw-dust,
powdered barks, straw, hemp, flax, linen, and cotton cloth, are
convertible by the action of strong sulphuric acid into a gummy
substance analogous to _dextrine_, and a sugar resembling that of the
grape.
If we put into a glass mortar 24 parts, by weight, of dry old cordage,
chopped small, and sprinkle over it 34 parts of sulphuric acid, by
degrees, so as to avoid heating the mixture, while we constantly stir
it; and if, in a quarter of an hour, we triturate the mass with a glass
pestle, the fibres will disappear without the disengagement of gas. A
tenacious mucilage will be produced, almost entirely soluble in water.
The gum being thus formed, may be separated from the acid by dilution
with water, and addition of the requisite quantity of chalk; then
straining the saturated liquid through linen cloth, concentrating it by
evaporation, throwing down any remaining lime by oxalic acid, filtering
anew, and mixing the mucilage with alcohol in great excess, which will
take up the free acid, and throw down the gum. From 24 parts of hemp
fibres thus treated, fully 24 parts of a gummy mass may be obtained,
containing, however, probably some water.
When, instead of saturating the diluted acid paste with chalk, we boil
it for 10 hours, the gummy matter disappears, and is replaced by sugar,
which may be purified without any difficulty, by saturation with chalk,
filtration, and evaporation to the consistence of syrup. In 24 hours
crystallization begins, and, in 2 or 3 days, a concrete mass of grape
sugar is formed; which needs merely to be pressed strongly between old
linen cloths doubled, and then crystallized a second time. If this syrup
be treated with bone black, a brilliant white sugar will be procured. 20
parts of linen rags yield 23 of good sugar. _Braconnot_. Guerin got
87-1/2 of dry sugar from 100 parts of rags, treated with 250 of
sulphuric acid. See WOOD.
FIBRINE, (Eng. and Fr.; _Thierischer Faserstoff_, Germ.) constitutes the
principal part of animal muscle; it exists in the chyle, the blood, and
may be regarded as the most abundant constituent of animal bodies. It
may be obtained in a pure state by agitating or beating new drawn blood
with a bundle of twigs, when it will attach itself to them in long
reddish filaments, which may be deprived of colour by working them with
the hands under a streamlet of cold water, and afterwards freed from any
adhering grease by digestion in alcohol or ether.
Fibrine, thus obtained, is solid, white, flexible, slightly elastic,
insipid, inodorous, denser than water, but containing 4 fifths of its
weight of it, and without action on litmus. When dried, it becomes
semi-transparent, yellowish, stiff, and brittle: water restores its
softness and flexibility. 100 parts of fibrine consist of 53·36 carbon,
19·68 oxygen, 7·02 hydrogen, and 19·31 azote. As the basis of flesh, it
is a very nutritious substance, and is essential to the sustenance of
carnivorous animals.
FILE (_Lime_, Fr.; _Feile_, Germ.), is a well known steel instrument,
having teeth upon the surface for cutting and abrading metal, ivory,
wood, &c.
When the teeth of these instruments are formed by a straight sharp-edged
chisel, extending across the surface, they are properly called files;
but when by a sharp-pointed tool, in the form of a triangular pyramid,
they are termed rasps. The former are used for all the metals, as well
as ivory, bone, horn, and wood; the latter for wood and horn.
Files are divided into two varieties, from the form of their teeth. When
the teeth are a series of sharp edges, raised by the flat chisel,
appearing like parallel furrows, either at right angles to the length of
the file, or in an oblique direction, they are termed _single cut_. But
when these teeth are crossed by a second series of similar teeth, they
are said to be _double cut_. The first are fitted for brass and copper,
and are found to answer better when the teeth run in an oblique
direction. The latter are suited for the harder metals, such as cast and
wrought iron and steel. Such teeth present sharp angles to the
substance, which penetrate it, while single cut files would slip over
the surface of these metals. The double cut file is less fit for filing
brass and copper, because its teeth would be very liable to become
clogged with the filings.
Files are also called by different names according to their various
degrees of fineness. Those of extreme roughness are called rough; the
next to this is the bastard cut; the third is the second cut; the
fourth, the smooth; and the finest of all, the dead smooth. The very
heavy square files used for heavy smith-work, are sometimes a little
coarser than the rough; they are known by the name of rubbers.
Files are also distinguished from their shape, as flat, half-round,
three-square, four-square, and round. The first are sometimes of uniform
breadth and thickness throughout, and sometimes tapering. The cross
section is a parallelogram. The half-round is generally tapering, one
side being flat, and the other rounded. The cross section is a segment
of a circle, varying a little for different purposes, but seldom equal
to a semi-circle. The three-square generally consists of three equal
sides, being equilateral prisms, mostly tapering; those which are not
tapering are used for sharpening the teeth of saws. The four-square has
four equal sides, the section being a square. These files are generally
thickest in the middle, as is the case with the smith’s rubber. In the
round file, the section is a circle, and the file generally conical.
The heavier and coarser kinds of files are made from the inferior marks
of blistered steel. Those made from the Russian iron, known by the name
of old sable, called from its mark CCND, are excellent. The steel made
from the best Swedish iron, called hoop L or Dannemora, makes the finest
Lancashire files, for watch and clock makers; a manufacture for which
the house of Stubbs in Warrington is celebrated.
The steel intended for files is more highly converted than for other
purposes, to give them proper hardness. It should however be
recollected, that if the hardness be not accompanied with a certain
degree of tenacity, the teeth of the file break, and do but little
service.
Small files are mostly made of cast steel, which would be the best for
all others, if it were not for its higher price. It is much harder than
the blistered steel, and from having been in the fluid state, is
entirely free from those seams and loose parts so common to blistered
steel, which is no sounder than as it comes from the iron forge before
conversion.
The smith’s rubbers are generally forged in the common smith’s forge,
from the converted bars, which are, for convenience, made square in the
iron before they come into this country. The files of lesser size are
made from bars or rods, drawn down from the blistered bars, and the cast
ingots, and known by the name of tilted steel.
The file-maker’s forge consists of large bellows, with coak as fuel. The
anvil-block, particularly at Sheffield, is one large mass of mill-stone
girt. The anvil is of considerable size, set into and wedged fast into
the stone; and has a projection at one end, with a hole to contain a
sharp-edged tool for cutting the files from the rods. It also contains a
deep groove for containing dies or bosses, for giving particular forms
to the files.
The flat and square files are formed entirely by the hammer. One man
holds the hot bar, and strikes with a small hammer. Another stands
before the anvil with a two-handed hammer. The latter is generally very
heavy, with a broad face for the large files. They both strike with such
truth as to make the surface smooth and flat, without what is called
hand-hammering. This arises from their great experience in the same kind
of work. The expedition arising from the same cause is not less
remarkable.
The half-round files are made in a boss fastened into the groove above
mentioned. The steel being drawn out, is laid upon the rounded recess,
and hammered till it fills the die.
The three-sided files are formed similarly in a boss, the recess of
which consists of two sides, with the angle downwards. The steel is
first drawn out square, and then placed in a boss with an angle
downwards, so that the hammer forms one side, and the boss two. The
round files are formed by a swage similar to those used by common
smiths, but a little conical.
The file-cutter requires an anvil of a size greater or less,
proportioned to the size of his files, with a face as even and flat as
possible. The hammers weigh from one to five or six pounds. The chisels
are a little broader than the file, sharpened to an angle of about 20
degrees. The length is just sufficient for them to be held fast between
the finger and thumb, and so strong as not to bend with the strokes of
the hammer, the intensity of which may be best conceived by the depth of
the impression. The anvil is placed in the face of a strong wooden post,
to which a wooden seat is attached, at a small distance below the level
of the anvil’s face. The file is first laid upon the bare anvil, one end
projecting over the front, and the other over the back edge of the same.
A leather strap now goes over each end of the file, and passes down upon
each side of the block to the workman’s feet, which, being put into the
strap on each side, like a stirrup, holds the file firmly upon the anvil
as it is cut. While the point of the file is cutting, the strap passes
over one part of the file only, the point resting upon the anvil, and
the tang upon a prop on the other side of the strap. When one side of
the file is single cut, a fine file is run slightly over the teeth, to
take away the roughness; when they are to be double cut, another set of
teeth is cut, crossing the former nearly at right angles. The file is
now finished upon one side, and it is evident that the cut side cannot
be laid upon the bare anvil to cut the other. A flat piece of an alloy
of lead and tin is interposed between the toothed surface and the anvil,
while the other side is cut, which completely preserves the side already
formed. Similar pieces of lead and tin, with angular and rounded
grooves, are used for cutting triangular and half-round files.
Rasps are cut precisely in the same way, by using a triangular punch
instead of a flat chisel. The great art in cutting a rasp is to place
every new tooth as much as possible opposite to a vacancy.
Many abortive attempts have been made to cut the teeth of files by
machinery. The following plan, for which a patent was obtained by Mr.
William Shilton, of Birmingham, in April 1833, is replete with ingenious
mechanical resources, and deserves to succeed.
The blanks of steel for making the files and rasps, are held in a pair
of clamps in connexion with a slide, and are moved forward at intervals
under the head of the tilt hammer which carries the tool; the distance
which the blank is to be advanced at every movement being dependent upon
the required fineness or coarseness of the cut of the file, which
movement is effected and regulated by a rack and pinion, actuated by a
pall and ratchet wheel, or the movement may be produced by any other
convenient means.
When the machine is employed for cutting or indenting the teeth of
rasps, the cutting tool being pointed and only producing one tooth at a
blow, the tilt hammer carrying the tool must be made to traverse at
intervals across the width of the blank piece of steel from one edge to
the other and back again; the blank being advanced in length only when
the hammer has produced the last cut or tooth toward either edge of the
rasp.
In order to render this invention better understood, two views of the
apparatus for producing the cross-cut or teeth of the files, are given.
[Illustration: 384* 385]
_Fig._ 384*. is an elevation of the upper part of the file-cutting
machine, as seen on one side; _fig._ 385. is a plan or horizontal view,
as the machine appears on the top.
_a_, is the head of the tilt hammer placed in the end of the lever _b_,
which is mounted on an axle _c_, turning in proper bearings in the frame
work of the machine; _d_, is the tilt wheel mounted on another axle _s_,
also turning in bearings on the frame work of the machine, and having
any required number of projections or tappets upon it for depressing the
tail or shorter end of the hammer or tilt lever _b_.