In Zinin's process the nitrobenzol is dissolved in alcohol, and the
solution, after the addition of ammonia, is saturated with sulphuretted
hydrogen. After standing some time the solution deposits a large quantity
of sulphur, and the liquid yields aniline.
Many other reducing agents have been proposed for the conversion of
nitrobenzol into aniline, such as arsenite of sodium, powdered zinc, &c.,
but on the large scale they have all been found inferior to the process of
Béchamp. Kremer's process consists in heating one part of nitrobenzol in a
proper apparatus with five of water and two and a half of zinc dust. When
the reaction is completed the aniline, amounting to about 65% of the
weight of the benzol, is distilled off in a current of steam.
_Prop., &c._ A thin, oily, colourless liquid, with a faintly vinous odour,
and a hot and aromatic taste; very volatile in the air; miscible in all
proportions with alcohol and ether; very slightly soluble in water;
neutral to ordinary test-paper, but exhibiting an alkaline reaction to
dahlia-petal infusion and paper; dissolves camphor, sulphur, and
phosphorus, and coagulates albumen; possesses a high refractive power; and
precipitates the oxides of iron, zinc, and alumina, from solutions of
their salts, and neutralises the acids, like ammonia. With the acids it
forms numerous crystallisable compounds of great beauty, and which are
easily formed, and are precisely analogous to the corresponding salts of
ammonia. These, on exposure to the air, acquired a rose colour, in many
cases gradually passing into brown. Its boiling-point is 359° to 360°
Fahr.; sp. gr. 1·028.
_Tests._--1. Chromic acid gives a deep greenish or bluish-black
precipitate with aniline and its salts:--2. Hypochlorite of lime strikes
an extremely beautiful violet colour, which is soon destroyed:--3. The
addition of two or three drops of nitric acid to anhydrous aniline
produces a fine blue colour, which, on the application of heat, passes
into yellow, and a violent reaction ensues, sometimes followed by
explosion:--4. With bichloride of platinum it yields a double salt
(platino-chloride of aniline) analogous to the like salt of ammonia.
These reactions distinguish it from all other substances.
Commercial aniline is a mixture consisting in great part of aniline,
paratoluidine (solid), and orthotoluidine in variable proportions. In
addition it contains small amounts of metatoluidine, nitrobenzol, odorine,
&c., but for all practical purposes it may be regarded as a mixture of
aniline and toluidine. These anilines are obtained from a portion of the
light coal-tar naphtha boiling between certain temperatures, by treating
it first with nitric acid to convert it into the nitro-compounds, and then
reducing these with iron and acetic acid, as already described under
Béchamp's process. It is very plain that as the coal-tar naphtha contains
variable proportions of benzol and toluidine, the resulting product must
also vary in the quantities of aniline and toluidine it will contain. In
order to distinguish between various samples of commercial aniline,
Reimann submits them to fractional distillation and compares the results.
He places 100 c. c. of the sample to be tested in a retort fitted with a
thermometer and heated by means of an oil bath. The liquid as it distils
is received in a narrow graduated cylinder, and the amount that passes
over between every 5° C. (9° F.) is noted.
In order to obtain standards for comparison he first distilled a sample of
light aniline, or kuphaniline, as he terms it, then one of heavy aniline
or baraniline; afterwards mixtures of the two in varying proportions. In
the accompanying table the results are given.
-------------+------------------------------------------------------------------------
Centigrade {|K. 100 90 85 80 75 60 50 25 0
{|B. 0 10 15 20 25 40 50 75 100
-------------+------------------------------------------------------------------------
Below 180° | 8-1/2 7 2-1/2 5-1/2 7 ... 7 5-1/2 ...
180°--185° | 54 50 29-1/2 22 5-1/2 7 4-1/2 2-1/2 2
185°--190° | 34 34 56-1/2 55-1/2 55-1/2 37 7-1/2 4-1/2 1-1/2
190°--195° | ... 5 7-1/2 8-1/2 15 33 42 17 8
195°--200° | ... ... ... ... 9 ... 19 36 18
200°--205° | ... ... ... ... 4-1/2 16 10 16 39
205°--210° | ... ... ... ... ... ... 3-1/2 8 19
210°--215° | ... ... ... ... ... ... ... 4-1/2 7
Residue | 3-1/2 4 4 8-1/2 3-1/2 7 6-1/2 5 5-1/2
-------------+------------------------------------------------------------------------
To ascertain the quality of any sample it is only necessary to distil it
in the manner already described, and compare the results with those in the
above table.
(For further information consult Wagner's 'Chemical Technology,' Calvert's
'Dyeing and Calico Printing,' edited by Stenhouse and Groves; Crooke's
'Practical Handbook of Dyeing and Calico Printing,' Ure's Dictionary,
edited by Hunt.)
_Uses_, _&c_. Chiefly in dyeing, for the production of colouring matter of
various rich shades of purple and violet, some approaching pink, by the
action of chromic acid; and of a splendid crimson, by the action of
various oxidising agents. It forms the basis of the celebrated new dyes
for silks lately patented by Mr W. H. Perkin, and others, and which are
not only more delicate and gorgeous in tint, but also more permanent, than
any produced by other substances.
Besides numerous salts, various substitution compounds of aniline have
been formed, all of which possess vast scientific interest, and several
are likely to prove of importance in the arts. See DYEING, INDIGO, TAR
COLOURS, &c. (also _below_.)
=Aniline, Chro'mates of=. _Prep_. 1. (NEUTRAL CHROMATE.) From sulphate or
oxalate of aniline and chromate of potash, by double decomposition.
2. (BICHRO'MATE:--Mr W. H. Perkin.) Sulphate of aniline and bichromate of
potash, in equivalent quantities, are separately dissolved in water, and
the solutions, after being mixed, are allowed to stand for several hours.
The whole is then thrown upon a filter, and the black precipitate which
forms is washed and dried. It is next digested in coal-tar naphtha (--?
benzol), to extract a brown resinous substance; after which it is digested
in alcohol, to dissolve out the colouring matter (BICHROMATE OF ANILINE),
which is left behind on distilling off the spirit, as a coppery friable
mass. Patented.
=Aniline, Cy'anide of=. Benzonitrile.
=Aniline, Ox'alate of=. (C_{6}H_{7}N)_{2}C_{2}O_{4}. Obtained by
saturating an alcoholic solution of oxalic acid with aniline; the salt
separating as a crystalline mass. It is very soluble in hot water; much
less so in cold water; only slightly soluble in alcohol; and insoluble in
ether. It may be crystallised from hot water or boiling alcohol. Used
chiefly to form other salts.
=Aniline, Sul'phate of=. (C_{6}H_{7}N)_{2}SO_{4}. Prepared by saturating
aniline with dilute sulphuric acid, and gently evaporating the liquid
until the salt separates. By re-solution in boiling alcohol, it
crystallises out, as the liquor cools, under the form of very beautiful
colourless plates, of a silvery lustre. It is freely soluble in water, and
in hot alcohol; scarcely soluble in cold alcohol; and insoluble in ether.
It is chiefly employed in the preparation of the new aniline dyes.
=ANIMAL'CULE= (-k[=u]le). [Eng., Fr.; pl. animal'cules.] _Syn._
ANIMAL'CULUM (pl., animal'cula[66]), L.; THIERCHEN, Ger. In _zoology_ and
_physiology_, a microscopic animal, or one so extremely small, that it is
either invisible, or not distinctly discernible, without the aid of a lens
or microscope; more especially one that is not perceptible to the naked
eye. "A mite was anciently thought the limit of littleness; but there are
animals 27,000,000 of times smaller than a mite." A thousand millions of
some of the animalcula found in common water are said to be collectively
of less bulk than a single grain of sand; yet their numbers are so
prodigious as sometimes to give the fluid they inhabit a pale red or
yellow tinge. The milt of a single codfish is said to contain more of
these minute animals than there are people in the whole earth. Animalcula
were first scientifically observed by Leuwenhoek about the year 1677.
Assisted by the microscope he unveiled, as it were, he created a new world
for future naturalists and microscopists to explore.
[Footnote 66: Animalculæ for the plural, sometimes heard and met with, is
a barbarism; yet one not wholly confined to the vulgar, for we find it in
Vincent's edition of Haydn's admirable 'Dict. of Dates,' not merely twice,
or oftener, in the text, but as a 'title-word,' and also in some other
works where we might least expect it.]
"Take any drop of water," says Professor Rymer Jones, "from our rivers,
from our lakes, or from the vast ocean itself, and place it under the
microscope; you will find therein countless living beings moving therein
in all directions with considerable swiftness, apparently gifted with
sagacity, for they readily elude each other in the active dance they keep
up.... Increase the power of your glasses, and you will soon perceive
inhabiting the same drop, other animals compared to which the former were
elephantine in their dimensions, equally vivacious and equally gifted.
Exhaust the art of the optician, strain your eyes to the utmost, until the
aching sense refuses to perceive the little quivering movement that
indicates the presence of life, and you will find that you have not
exhausted nature in the descending scale."
Amongst the most remarkable discoveries of modern science must be reckoned
that of fossil animalcules in such abundance as to form the principal part
of extensive strata. This discovery is due to Ehrenberg, who found the
Polierschiefer (the polishing slate or tripoli) of Bilin to be almost
entirely made up of the siliceous shields of a minute fossil animalcule,
the length of one of which is about 1/288th of a line, so that about
23,000,000 of animalcules must have gone to form a cubic line, and
41,000,000,000 to form a cubic inch of the rock. Ehrenberg succeeded in
discovering the formation of similar strata in deposits of mud at the
bottom of lakes and marshes, the mud swarming with living animalcules,
probably in their turn to be fossilised. The bergmehl, or mountain meal of
Sweden and other parts of Europe, which is sometimes used as an article of
food, is entirely composed of the remains of animalcules; not merely,
however, of their siliceous shields, for it contains a considerable
per-centage of dry animal matter. Some animalcules prefer waters
impregnated with iron, and their death gives rise to an ochreous substance
in which iron is a principal ingredient.
=AN'IME= ([)a]n'-[)i]m-e). [Eng., L., Sp.] _Syn._ GUM-AN'IME, A.-RES'IN;
ANIMÉ, Fr.; ANIMEHARZ, KOURBARILLHARZ, Ger.; COURBARIL, JUTAIBA, Nat. A
pale brownish-yellow, transparent, brittle resin, which exudes from the
_hymenæa courbaril_ (Linn.) or locust-tree, the _h. martiana_, and other
species of hymenæa growing in tropical America. It contains about ·2% of
volatile oil, which gives it an agreeable odour; melts without
decomposition; is (nearly) insoluble in alcohol and in caoutchoucine, but
forms a gelatinous mass in a mixture of the two. (Ure.) It burns readily,
emitting a very fragrant smell. Sp. gr. 1·054 to 1·057.
_Uses, &c._ As a fumigation in spasmodic asthma; in solution as an
embrocation; and in powder as a substitute for gum guaiacum. In this
country it is chiefly employed to make varnishes and pastilles (which
_see_).
=AN'ION= (-y'[)u]n--Br., We.; [)a]-n[=i]'-[)u]n--Smart). Literally,
'upward going,' in _electro-chemistry_, a substance which is evolved from
the surface where the electrical current is supposed to enter the
electrolyte; an electro-negative body, or one which passes to the positive
pole, or anode, in electrolysis, as opposed to a CATION. See ANODE, IONS,
&c.
=AN'ISATED.= _Syn._ ANISA'TUS, L.; ANISÉ, Fr. In _pharmacy_, the art of
the liqueuriste, confectioner, &c., applied to articles or preparations
impregnated or flavoured with aniseed.
=AN'ISE= (-[)i]s). _Syn._ ANI'SUM, PIMPINEL'LA A. (Linn.), A. OFFICINA'LE,
L.; ANIS, Fr.; ANIS, GEMEINER ANIS, Ger. An annual plant of the nat. ord.
Umbelliferæ (DC.). _Hab._, Egypt, Scio, and the Levant; but largely
cultivated in Malta, Spain, Germany, and various other parts of Asia and
Europe. "A considerable quantity is cultivated at Mitcham, in Surrey,
chiefly for the use of the rectifiers of British spirits." (Stephenson.)
Fruit, aniseed. (See _below_.)
=AN'ISEED.= _Syn._ AN'ISE, AN'ISE-SEED; SEM'INA ANI'SI, FRUC'TUS A., L.;
ANIS, A. VRAI, GRAINES D'ANIS, SEMENCE D'ANIS, Fr.; ANIS, ANISAMEN, Ger.;
ANIS, Sp.; ANICE, It. The aromatic fruit or seed of the _pimpinella
anisum_ just noticed.
_Prop., Uses, &c._ Its aromatic properties depend on the presence of
volatile oil. The seed and oil, and a spirit and a water prepared from
them, are officinal in the pharmacop[oe]ias. Both the seed and its
preparations are reputed stimulant, stomachic, carminative, pectoral,
diuretic, and emmenagogue. They are commonly used to relieve flatulence
and colicky pains, and to prevent the griping effects of certain
cathartics; and they have long been popular remedies for coughs, colds,
and other breath ailments. They are esteemed especially useful in warming
the stomach and expelling wind, particularly during infancy and childhood;
the distilled or flavoured water being usually employed. Nurses also take
the latter to promote the secretion of milk, to which it at length imparts
its peculiar odour and flavour. In _veterinary practice_ the powdered seed
is used as a carminative, pectoral, and corroborant. The essential
oil is said to be poisonous to pigeons. (Vogel; Hillefield.)
Aniseed is principally used to flavour liqueurs, sweetmeats, and
confectionery.--_Dose_ (of the powder), 10 gr. to 1 or 2 dr.; for a horse,
1/2 to 1 oz.; cattle, 3/4 to 2 oz.
_Pur., &c._ Powdered aniseed is nearly always adulterated, the adulterant
being generally linseed meal. Sometimes, as for the horse, the latter is
entirely substituted for it, a few drops of oil of aniseed being added to
give it smell. The adulteration is not readily detected by the
uninitiated, owing to the strong odour of aniseed; but readily by the
microscope. The fruit of _myrrhis odorata_ (sweet cicily), and of
_illicium anisatum_ (star-anise), also possess the odour and flavour of
common aniseed; indeed, most of the essential oil now sold as 'oil of
aniseed' is star-anise oil. See LIQUEURS, OILS, SPIRITS, WATERS, &c.
=Anise, Star'.= The fruit or seed of _illi''cium anisa'tum_ (Linn.), an
evergreen tree growing in Japan and China. The odour and properties of
both the seed and oil greatly resemble those of common anise. They are
both employed by the liqueuriste. See ANISEED (_above_), &c.
=ANISETTE'= ([)a]n-[)i]z-[)e]t'). [Fr.] Aniseed cordial. See LIQUEURS.
=ANISOCHILUS CARNOSUM.= Nat. order LABIATÆ. An Indian plant. It is
stimulant, diaphoretic, and expectorant; is used in quinsy, and by the
native doctors of Travancore in catarrhal affections. Dr Bidie, an Indian
practitioner, characterises it as a mild stimulating expectorant, and as
such particularly useful in the coughs of childhood. Its properties depend
upon a volatile oil.
=ANISOMELES MALABARICA.= An Indian plant. Nat. order Labiatæ. Few plants
are held in higher esteem, or more frequently employed in native practice
in Southern India, than this. An infusion made of the leaves is very
generally used in affections of the stomach and bowels, catarrhal
complaints, and intermittent fevers.
Dr Wright says that in addition to its internal use in the case of fevers,
patients are made to inhale the vapour of a hot infusion, so as to induce
copious diaphoresis. An infusion of the leaves is reported to be
powerfully diaphoretic, and to have been found very useful in the low
continuous fevers of the natives. An oil obtained by distillation from the
leaves is likewise stated to be an effectual external application in
rheumatism.
=ANI'SUM.= Aniseed.
=ANNEAL'ING.= _Syn._ NEALING[dagger]§; LE RECUIT, Fr.; DAS ANLASSEN, Ger.
The art of tempering by heat: appropriately, the process by which glass,
porcelain, &c., are rendered less frangible, and metals which have become
brittle by fusion, or long-continued hammering, again rendered tough and
malleable.
Glass vessels, and other articles of glass, are annealed by being placed
in an oven or apartment near the furnaces at which they are formed, called
the 'leer,' where they are allowed to cool very slowly, the process being
prolonged in proportion to their bulk.
Steel, iron, and other metals are annealed by heating them and allowing
them to cool slowly on the hearth of the furnace, or in any other suitable
place, unexposed to the cold. Steel is also annealed by being made
red-hot, and in that state is placed in a heap of dry saw-dust till cold,
when it will be found quite soft.
Cast-iron is rendered tough and malleable, without 'puddling,' by
embedding it in ground charcoal or hæmatite, and thus protected, keeping
it exposed at a high temperature for several hours, after which the whole
is allowed to cool very slowly.
Prince Rupert's drop may be mentioned as an example of unannealed glass,
and common cast-iron of unannealed metals, to which heads the reader is
referred.
=ANNOT'TA.= _Syn._ ANOT'TO, ANNAT'TO, ANNAT'TA; ARNAT'TO, ARNOT'TO, &C.;
ORLEA'NA, TER'RA O.*, &c., L.; ROUCOL, ROCOU, ROUCOU, Fr.; ORLEANS, Ger. A
colouring matter forming the outer pellicle of the seeds of the _bix'a
orella'na_ (Linn.), an exogenous evergreen tree, common in Cayenne and
some other parts of tropical America, and now extensively cultivated in
both the E. and W. Indies. It is usually obtained by macerating the
crushed seeds or seed-pods in water for several weeks, ultimately allowing
the pulp to subside, which is then boiled in coppers to a stiff paste, and
dried in the shade. Sometimes a little oil is added in making it up into
cakes or lumps. A better method is that proposed by Leblond, in which the
crushed seeds are simply exhausted by washing them in water (--?
alkalised), from which the colouring matter is then precipitated by means
of vinegar or lemon-juice; the precipitate being subsequently collected,
and either boiled up in the ordinary manner, or drained in bags and dried,
as is practised with indigo. Annotta so prepared is said to be four times
as valuable as made by the old process.
_Prop._ Good annotta is of a brilliant red colour; brighter in the middle
than on the outside; feels soft and smooth to the touch; has a good
consistence, and a strongly characteristic but not a putrid smell. It is
scarcely soluble in water; freely soluble in alcohol, ether, oils, and
fats, to each of which it imparts a beautiful orange colour, and in
alkaline solutions which darken it; acids precipitate it of an orange red
hue; strong sulphuric acid turns it blue. Its most important property is
the affinity of its colouring matter for the fibres of silk, wool, and
cotton.
_Pur._ Annotta is very frequently adulterated; indeed, nearly always so.
To what extent the sophistication of annotta is carried may be judged from
the statement of Mr Blyth, who says that on examination of thirty-four
samples of various kinds, as imported and obtained from English makers and
as purchased from dealers, he found only two that were genuine. As annotta
is often used to give colour to different articles of diet, it is
important that it should be as pure as possible; otherwise injurious
effects detrimental to health may be caused by partaking of any food to
which it is added. Now, amongst the list of adulterants given below are
three, at least, unmistakeable poisons, viz. red lead, orange chrome, and
sulphate of copper. It is but right to state of the first of these
substances (red lead) that Mr Blyth says it is extremely doubtful whether
it is now employed to the extent it formerly was. He also ascribes its
presence in annotta to the impure Venetian red which is used, the
employment of this colour being a necessity because of the large
quantities of flour and lime which are mixed with the annotta, which
thereby becomes so reduced in colour that it is essential to have recourse
to salt, alkalies, and the red earths to restore it to its original
standard. The adulterants are generally meal, flour, or farina, and often
chalk or gypsum, with some pearlash and oil, or even soap, to give it an
unctuous character; turmeric, Venetian red, red ochre, orange chrome, or
even red lead, to give it 'colour,' and common salt, and sometimes even
sulphate of copper, to prevent decomposition--the last two being
poisonous. Sometimes a little carbonate of ammonia is also added to it to
improve the colour. When quite pure it contains about 28% of resinous
colouring matter, and 20% of colouring extractive matter (Dr John), and
should leave only a small quantity of insoluble residuum after digestion
in alcohol, whilst the ash resulting from its incineration should not
exceed 1-1/2 to 2%. The quantity, colour, &c., of the ash will give an
easy clue to the inorganic adulterants, if any are present, which may be
then followed up by a chemical examination. The presence of red lead may
be detected by heating it on a piece of charcoal in the reducing flame of
the blowpipe, by which a small bead of metallic lead will be obtained. If
it contains chalk, ochre, gypsum, &c., the undissolved residuum of the
washed ash gives the amount of the adulteration (nearly).
_Microscopical Examination of Annotta._--When annotta is subjected to a
microscopical examination the outer red portion will be found to present
an almost homogeneous appearance, whilst the surface of the seed proper
will be seen to consist of narrow or elongated cells or fibres disposed in
a vertical direction, while the inner white portion will be seen to be
made up of cells filled with starch corpuscles, well defined, of medium
size, and resembling in the elongated and stellate hilum the starch
granules of the pea and bean.
When the annotta is manufactured, and an unadulterated sample is examined,
but little structure is met with. Portions of the outer cells may be seen;
and in those samples which in the course of their preparation have not
been subjected to the action of boiling water, a few starch granules may
be observed.
Since annotta, when manufactured, presents so few evidences of structure,
we are easily able, with the microscope at our command, to detect the
presence of most foreign vegetable substances. These consist of turmeric
powder, wheat, rye and barley starch, and sago flours. The salt and alkali
present in the fraudulent annotta generally greatly alter the appearance
of the turmeric. Most of the colouring matter of the cells is discharged,
so that the starch corpuscles contained within them become visible. Loose
starch granules of turmeric may also be frequently seen, and in a much
enlarged condition, owing to the action of the alkali upon them.
The following process for conducting the assay of annotta is given by Mr
Blyth:--
"In order to estimate the commercial value and detect adulteration in a
sample, the quickest and best way is the following: Weigh accurately a
gramme in a small platinum dish; dry in the water-bath for a couple of
hours, then weigh; the loss is the water. Finely powder, and digest it for
some hours in alcohol; then boil, filter and treat with successive
portions of alcohol until all the colouring-matter is dissolved; filter,
evaporate the filtrate down and weigh; the result is the resin. The
insoluble portion will in a good commercial specimen consist of woody
matter, extractive, gluten, &c. For the ash weigh another gramme in a
platinum dish; dry for a short time over the water-bath; then powder and
burn until it ceases to lose weight. It is prudent to fuse a little on
charcoal with carbonate of soda before the blow-pipe before burning it in
a platinum vessel, as there may be lead in the annotta. The ash should
then be submitted to the various reagents in order to detect lime,
alumina, &c. A correct determination of ash and resin is all that is
required to definitely pronounce upon the purity or impurity of the
samples."