_alchemy_, a term applied to various preparations without any precise
meaning. "Arcanum is a thing secret, incorporeal, and immortal, which can
only be known to man by experience; for it is the virtue of each thing,
which operates a thousand times more than the thing itself." (Ruland) In
_ancient medicine_ and _pharmacy_; a nostrum. The word is still
occasionally used in the plural (ARCA'NA, secrets, mysteries), in the
titles of books; as, 'Arcana of Chemistry,' a book professing to contain a
full exposition of the mysteries of that art.
Among the old chemists, ARCANUM AL'BUM was 'pulvis Viennensis albus
virgineus' (see POWDERS); A. BEC'CHICUM, a sweetened aqueous solution of
liver of sulphur; A. CORALLI'NUM, red oxide of mercury that had been
digested in a solution of potash, washed with water, and then had spirit
of wine burnt on it (once a favourite mercurial and escharotic); A.
DUPLICA'TUM, sulphate of potash; A. D. CATHOL'ICUM, roots of colchicum and
plantain (worn as an amulet against fevers and pestilential diseases); A.
LUDEMAN'NI, oxide of zinc; A. TAR'TARI, acetate of potassa; A. VI'TÆ,
elixir vitæ; &c.
=ARCHE'US= (-k[=e]'-[)u]s; [)a]r'*--Mayne). [L.] _Syn._ ARCHÆ'US, L. A
term invented by Paracelsus, and employed by the alchemists and older
physicians, to imply the occult cause of phenomena, as well as the
sub-causes or agents by which the effects were accomplished. Van Helmont
and Stahl ascribe certain vital functions to the influence and
superintendence of a 'spiritus archæus' or intelligent vital principle.
According to others, the powers of 'Archæus' were indefinitely extended.
He or it was an occult power of nature, the artificer of all things,
physician-general to the universe, &c. &c., to the utmost bounds of
absurdity and confusion.
From this word comes the adj. ARCHE'AL or ARCHÆ'AL, hidden, operative.
=ARCH'IL= (artsh'-[)i]l). _Syn._ ARCH'EL*, OR'CHIL; ARCHIL'LA, ORCHIL'LA
(ch as k), L.; ORSEILLE, Fr., Ger.; ORICELLO, It. A violet-red, purple or
blue colouring matter or dye-stuff, obtained from several species of
lichens, but of the finest quality from roccella tinctoria (DC.), and next
from r. fuciformis (DC.).
The archil of commerce is met with as a liquid paste, or as a thin liquid
dye or stain of more or less intensity. The ordinary archil or orchil of
the shops (ORCHIL-LIQUOR) is under the last form; and is known as either
BLUE OR RED ARCHIL--distinctions which arise as follows:--
_Prep._ 1. BLUE ARCHIL:--The bruised or coarsely ground lichen is steeped
for some time in a mixture of stale urine, or bone-spirit, and lime or
milk of lime, or in any similar ammoniacal solution, contained in covered
wooden vessels in the cold; the process being repeated until all the
colour is extracted.
2. RED OR CRIMSON ARCHIL:--The materials are the same as for the last
variety, but rather less milk of lime is used, and the 'steep' is
generally made in earthen jars placed in a room heated by steam,
technically called a stove. The two kinds merely differ in the degree of
their red or violet tint--the addition of a small quantity of lime or
alkali to the one, or of an acid to the other, immediately bringing them
both to the same shade of colour.
_Prop._ Archil has a disagreeable putrid ammoniacal odour. Its colouring
matter is soluble in water, alcohol, urine, ammoniacal and alkaline lyes,
and weak acid liquors; alkalies turn it blue, acids red; alum gives with
it a brownish-red precipitate, and solution of tin a red one; the
alcoholic solution gradually loses its colour when excluded from the air.
Its colouring matter consists chiefly of orcein.
_Pur._ Archil is frequently adulterated with extract of logwood, or of
Lima or Sapan-wood. It may be tested as follows:--1. A solution of 50 or
60 drops of pure archil in about 3 fl. oz. of water slightly acidulated
with acetic acid, almost entirely loses its colour, or presents only a
yellowish tinge, when heated to ebullition in a flask along with 50 drops
of a fresh solution of protochloride of tin made with 1 part of the salt
to 2 parts of water:--2. A drop of fluid extract of logwood treated in the
same way, gives a distinct violet tint, which resists several hours'
boiling; but when only 3 or 4 per cent. of logwood is present, the boiled
liquid has a permanent grey tint:--3. If the boiled liquid retains its red
hue, extract of Sapan-wood is present:--4. The boiled liquor, when the
archil is pure, re-acquires its colour by exposure to the air, and the
addition of an alkali, particularly ammonia; whilst the colour produced by
logwood is destroyed only by an alkaline solution of tin, and is restored
by acids.
_Uses, &c._ It is employed to tinge the spirit used to fill the tubes of
thermometers, and to stain paper, wood, &c. The aqueous solution stains
MARBLE, in the cold, of a beautiful violet colour, of considerable
permanence when not exposed to a vivid light. "Marble thus tinged
preserves its colour unchanged at the end of two years." (Dufay.) Its
principal use is, however, in dyeing. By proper management it may be made
to produce every shade of pink and crimson to blue and purple.
Unfortunately, although the hues it imparts to silk and wool possess an
exquisite bloom or lustre, they are far from permanent, and unless well
managed, soon decay. It is hence generally employed in combination with
other dye-stuffs, or as a finishing bath to impart a bloom to silk or
woollens already dyed of permanent colours. In using it as a dye it is
added to hot water in the required quantity, and the bath being raised to
nearly the boiling-point, the materials are put in and passed through it,
until the desired shade is produced. A mordant of alum and tartar is
sometimes used, but does not add to the permanence of the colour. Solution
of tin added to the bath increases the durability, but turns the colour
more on the scarlet. (Hellot.) Milk of lime or salt of tartar is added to
darken it; acids or solution of tin to redden it. A beautiful crimson-red
is obtained by first passing the stuff through a mordant of tin and
tartar, and then through a bath of archil mixed with a very little
solution of tin. By the proper management of this dye, lilacs, violets,
mallows, rosemary flower, soupes au vin, agates, and many other shades may
be produced on silk or cloth, either alone or in conjunction with other
dyes to modify it. 1/2 _lb._ of solid archil, or its equivalent in a
liquid form, will dye 1 to 2 _lb._ of cloth. HERB-ARCHIL, it is asserted,
will bear boiling, and gives a more durable tint than the other lichens,
especially with solution of tin. (Hellot.) Recently Mr Lightfoot has
patented a process for dyeing with archil with the aid of oil, after the
manner followed for producing Turkey-red on cottons.
Archil, Facti''tious:--1. From a mixture of onions (in a state of
incipient putrefaction) with about 1-10th to 1-12th their weight of
carbonate of potash and some ammonia, fermented together; and adding,
after some days, 1-7th to 1-8th of the weight of the potash used in a salt
of lead. The details of the process essential to success are, however, now
unknown, the secret having died with a relative of the writer of this
article.
2. Extract of logwood dissolved in juice of elderberries and putrid urine,
with the addition of a little pearlash for the BLUE, and a very little
oxalic acid or oil of vitriol for the RED variety. Used to stain wood.
=Arch'il, Herb.= Roccella tinctoria. See ARCHIL (_above_), LICHENS, and
MOSSES.
=ARE= ([)a]r; [=a]re--Eng.). [Fr.] See MEASURES.
=ARE'CA.= [L.] In _botany_ a genus of East Indian trees, of the nat. ord.
Palmæ (DC.).
=Areca Cate'chu.= [L.; Linn.] _Syn._ ARE'CA, A. IN'DICA, A. FAUFEL,
BE'TEL-NUT TREE. _Hab._ East Indies. Fruit (BETEL-NUT), astringent and
narcotic; husk of fruit (PENANG or PINANG), sialagogue and stomachic; both
are used as masticatories; wood and nut yield an inferior or bastard sort
of catechu; charcoal of the nut highly esteemed as tooth-powder; also
given in tape-worm in doses of 1/4 _oz._ and 1/2 _oz._; said to be more
efficacious in coarse than in fine powder.--_Doses for Animals_. HORSE, 4
to 6 drachms; CATTLE, 4 to 8 drachms; DOG, 30 grains to 2 drachms.
=Areca Globulif'era.= [L.] Properties similar to the last.
=Areca Olera'cea.= [L.; Willd.] Cabbage-palm.
=ARENA'CEOUS= ([)a]r-e-). _Syn._ ARENA'CEUS, L.; ARÉNACÉ, SABLONNEUX, Fr.;
SANDIG, SANDARTIG, Ger. In agriculture, mineralogy, &c., sandy; resembling
sand; friable.
=ARENA''RIOUS= (-nare'-). _Syn._ ARENA''RIUS, L.; ARÉNAIRE, Fr. Sandy,
arenaceous. In _agriculture_ and _botany_ applied to soils (ARENARIOUS
SOILS) in which sand is the prevailing and characteristic ingredient; also
to plants that grow in sandy or arid soils.
=ARENA'TION.= _Syn._ SABURRA'TION; ARENA'TIO, L.; ARÉNATION, Fr.; SANDBAD,
Ger. In _medicine_ sandbathing; a practice formerly prevalent, in dropsy,
of applying hot sand, either by immersion or otherwise, to the feet, legs,
or even the whole body.
=ARENOSE'= ([)a]r-e-n[=o]se'). _Syn._ AR'ENOUS*; ARENO'SUS, L.; ARÉNEUX,
Fr. Sandy; arenaceous (which _see_).
=AREOM'ETER= ([)a]-re- or [)a]r-re-; [=a]re-e--Smart). _Syn._ AREOM'ETRUM,
L.; ARÉOMÈTRE, Fr. Literally, a 'measure of lightness' or 'rarity,'
originally applied to any instrument for determining the specific gravity
of alcoholic and ethereal liquids; but since applied, like the word
'hydrometer,' to instruments adjusted to the densities of all liquids. In
this country the term is principally confined to the aréomètres of Baumé,
on account of their general use by Continental chemists. The relations and
equivalents of Baumé's scales, as now adopted in France, are shown in the
first two of the following _Tables_:--
I.--_Corresponding_ DEGREES of BAUMÉ'S AREOMETERS and REAL SPECIFIC
GRAVITIES:--
1. _Areometer for liquids_ LIGHTER _than_ WATER, or
_Pèse-esprit_.[77]
-------+--------+-------+--------+-------+--------+-------+--------+-------+--------
Degrees|Specific|Degrees|Specific|Degrees|Specific|Degrees|Specific|Degrees|Specific
Baumé. |Gravity.|Baumé. |Gravity.|Baumé. |Gravity.|Baumé. |Gravity.|Baumé. |Gravity.
-------+--------+-------+--------+-------+--------+-------+--------+-------+--------
10 | 1·0000 | 21 | 0·9300 | 32 | 0·8690 | 42 | 0·8202 | 52 | 0·7766
11 | 0·9932 | 22 | 0·9241 | 33 | 0·8639 | 43 | 0·8156 | 53 | 0·7725
12 | 0·9865 | 23 | 0·9183 | 34 | 0·8588 | 44 | 0·8111 | 54 | 0·7684
13 | 0·9799 | 24 | 0·9125 | 35 | 0·8538 | 45 | 0·8066 | 55 | 0·7643
14 | 0·9733 | 25 | 0·9068 | 36 | 0·8488 | 46 | 0·8022 | 56 | 0·7604
15 | 0·9669 | 26 | 0·9012 | 37 | 0·8439 | 47 | 0·7978 | 57 | 0·7556
16 | 0·9605 | 27 | 0·8957 | 38 | 0·8391 | 48 | 0·7935 | 58 | 0·7526
17 | 0·9542 | 28 | 0·8902 | 39 | 0·8343 | 49 | 0·7892 | 59 | 0·7487
18 | 0·9480 | 29 | 0·8848 | 40 | 0·8295 | 50 | 0·7849 | 60 | 0·7449
19 | 0·9420 | 30 | 0·8795 | 41 | 0·8249 | 51 | 0·7807 | 61 | 0·7411
20 | 0·9359 | 31 | 0·8742 | | | | | |
-------+--------+-------+--------+-------+--------+-------+--------+-------+---------
[Footnote 77: These instruments were originally adjusted at the
temperature of 12-1/2° Cent., or 54-1/2° Fahr. Those now made in France
are adjusted at 15° C., or 59° F.; and those made in England, at either
59° or (more usually) 60° Fahr. The standard temperature of the instrument
must be known for its correct application.]
2. _Areometer for liquids_ HEAVIER _than_ WATER;
_Pèse-acide_, or _Pèse-sirop_.[78]
+-------+--------+-------+--------+-------+--------+-------+--------+-------+--------+
|Degrees|Specific|Degrees|Specific|Degrees|Specific|Degrees|Specific|Degrees|Specific|
|Baumé. |Gravity.|Baumé. |Gravity.|Baumé. |Gravity.|Baumé. |Gravity.|Baumé. |Gravity.|
+-------+--------+-------+--------+-------+--------+-------+--------+-------+--------+
| 0 | 1·0000 | 16 | 1·1176 | 32 | 1·2667 | 47 | 1·4476 | 62 | 1·6889 |
| 1 | 1·0066 | 17 | 1·1259 | 33 | 1·2773 | 48 | 1·4615 | 63 | 1·7079 |
| 2 | 1·0133 | 18 | 1·1343 | 34 | 1·2881 | 49 | 1·4758 | 64 | 1·7273 |
| 3 | 1·0201 | 19 | 1·1428 | 35 | 1·2992 | 50 | 1·4902 | 65 | 1·7471 |
| 4 | 1·0270 | 20 | 1·1515 | 36 | 1·3103 | 51 | 1·5051 | 66 | 1·7674 |
| 5 | 1·0340 | 21 | 1·1603 | 37 | 1·3217 | 52 | 1·5200 | 67 | 1·7882 |
| 6 | 1·0411 | 22 | 1·1692 | 38 | 1·3333 | 53 | 1·5353 | 68 | 1·8095 |
| 7 | 1·0483 | 23 | 1·1783 | 39 | 1·3451 | 54 | 1·5510 | 69 | 1·8313 |
| 8 | 1·0556 | 24 | 1·1875 | 40 | 1·3571 | 55 | 1·5671 | 70 | 1·8537 |
| 9 | 1·0630 | 25 | 1·1968 | 41 | 1·3694 | 56 | 1·5833 | 71 | 1·8765 |
| 10 | 1·0704 | 26 | 1·2063 | 42 | 1·3818 | 57 | 1·6000 | 72 | 1·9000 |
| 11 | 1·0780 | 27 | 1·2160 | 43 | 1·3945 | 58 | 1·6170 | 73 | 1·9241 |
| 12 | 1·0857 | 28 | 1·2258 | 44 | 1·4074 | 59 | 1·6344 | 74 | 1·9487 |
| 13 | 1·0935 | 29 | 1·2358 | 45 | 1·4206 | 60 | 1·6522 | 75 | 1·9740 |
| 14 | 1·1014 | 30 | 1·2459 | 46 | 1·4339 | 61 | 1·6705 | 76 | 2·0000 |
| 15 | 1·1095 | 31 | 1·2562 | | | | | | |
+-------+--------+-------+--------+-------+--------+-------+--------+-------+--------+
II.--_Corresponding_ SPECIFIC GRAVITIES _and_ DEGREES _of_ BAUMÉ'S
AREOMETER _for heavy liquids_.[78] From the Batavian Pharmacop[oe]ia.
[Footnote 78: See footnote on previous page.]
+-------+--------+-------+--------+-------+--------+-------+--------+-------+--------+
|Degrees|Specific|Degrees|Specific|Degrees|Specific|Degrees|Specific|Degrees|Specific|
|Baumé. |Gravity.|Baumé. |Gravity.|Baumé. |Gravity.|Baumé. |Gravity.|Baumé. |Gravity.|
+-------+--------+-------+--------+-------+--------+-------+--------+-------+--------+
| 0 | 1000 | 16 | 1125 | 32 | 1286 | 47 | 1485 | 62 | 1758 |
| 1 | 1007 | 17 | 1134 | 33 | 1298 | 48 | 1501 | 63 | 1779 |
| 2 | 1014 | 18 | 1143 | 34 | 1309 | 49 | 1516 | 64 | 1801 |
| 3 | 1022 | 19 | 1152 | 35 | 1321 | 50 | 1532 | 65 | 1823 |
| 4 | 1029 | 20 | 1161 | 36 | 1334 | 51 | 1549 | 66 | 1847 |
| 5 | 1036 | 21 | 1171 | 37 | 1346 | 52 | 1566 | 67 | 1872 |
| 6 | 1044 | 22 | 1180 | 38 | 1359 | 53 | 1583 | 68 | 1897 |
| 7 | 1052 | 23 | 1190 | 39 | 1372 | 54 | 1601 | 69 | 1921 |
| 8 | 1060 | 24 | 1199 | 40 | 1384 | 55 | 1618 | 70 | 1946 |
| 9 | 1067 | 25 | 1210 | 41 | 1398 | 56 | 1637 | 71 | 1974 |
| 10 | 1075 | 26 | 1221 | 42 | 1412 | 57 | 1656 | 72 | 2000 |
| 11 | 1083 | 27 | 1231 | 43 | 1426 | 58 | 1676 | 73 | 2031 |
| 12 | 1091 | 28 | 1242 | 44 | 1440 | 59 | 1695 | 74 | 2059 |
| 13 | 1100 | 29 | 1252 | 45 | 1454 | 60 | 1715 | 75 | 2087 |
| 14 | 1108 | 30 | 1261 | 46 | 1470 | 61 | 1738 | 76 | 2116 |
| 15 | 1116 | 31 | 1275 | | | | | | |
+-------+--------+-------+--------+-------+--------+-------+--------+-------+--------+
=AREOM'ETRY.= _Syn._ AREOME'TRIA, L.; ARÉOMÉTRIE, Fr. The art or operation
of ascertaining the specific gravity of liquids, and hence also their
strength or commercial value; hydrometry. See AREOMETER (_above_),
HYDROMETRY, SPECIFIC GRAVITY, &c.
=ARE'CINA.= C_{23}H_{26}N_{2}O_{4}. An alkaloid discovered by Pelletier
and Comol, in white cinchona bark from Aréca. It is extracted from the
bark by the same process as Quinine, viz., by boiling the bark with
acidulated water, treating the liquor with lime, and digesting the
lime-precipitate in alcohol. The solution filtered at the boiling heat
yields a very dark-coloured liquid, which, after a time, deposits the
greater part of the aricine in crystals. An additional quantity may be
obtained from the mother-liquor by expelling the alcohol by distillation,
treating the residue with a slight excess of hydrochloric acid, separating
the greater part of the colouring matter by means of a saturated solution
of common salts, then throwing down the aricine by ammonia, dissolving the
precipitate in alcohol, decolourising with animal charcoal and
crystallising.
=ARGAMONE MEXICANA= (nat. order PAPAVERACEÆ). A tropical American plant,
now a common weed growing in almost every part of India. A fixed oil is
obtained from the seeds by expression, which has long been employed as an
aperient in the West Indies. In half-drachm doses it is said to act as a
gentle aperient, and at the same time it allays, apparently by its
sedative qualities, the pain in colic. The smallness of the dose, and the
mildness of its operation, commend it to the notice of the medical
practitioner. Its efficiency is impaired by keeping, the freshly prepared
oil proving more active and uniform in its action than that which has been
long on hand. It is reported to exercise a well-marked and soothing
influence when applied to herpetic eruptions and other forms of skin
disease. By the natives of India the expressed yellow glutinous juice of
the plant is held in high repute as a local application to indolent and
foul ulcers.
=ARGENT'INE= (-[)i]n). _Syn._ ARGENTI'NUS, L.; ARGENTIN, Fr.;
SILBERFARBEN, &c., Ger. Silver-like; pertaining to, resembling, or
sounding like silver; argental.
=Ar'gentine.= (-t[)i]n). [Eng., Fr.] German silver*. In _mineralogy_,
nacreous carbonate of lime, from its whiteness and silvery lustre.
=ARGENT'UM.= [L.] Silver. In _old chemistry_ and _pharmacy_, ARGENTUM,
FUGITI''VUM[dagger], A. MO'BILE[dagger] (-[)i]l-e), was quicksilver; A.
MOR'TUUM[dagger], dead silver, grain-s; A. MUSI'VUM[dagger], mosaic s.,
silver-bronze; A. NITRA'TUM[dagger], lunar caustic; A. VI'VUM[dagger],
quicksilver; A. ZOÖTIN'ICUM[dagger], cyanide of silver; &c.
=AR'GIL=[dagger] (j[)i]l). _Syn._ ARGIL'LA, L.; ARGILE, Fr. Clay or
potter's earth.
=ARGILLA'CEOUS= (-j[)i]l-). _Syn._ ARGILLA'CEUS, L.; ARGILLEUX, Fr.;
THONIG, THONARTIG, Ger. Clayey; pertaining to, containing, or of the
nature of clay or argil. In _agriculture_, an epithet of soils
(ARGILLACEOUS SOILS) of which clay is the principal or characteristic
ingredient.
=Argil'lo-arena'ceous= (-j[)i]l-). In _agr._, consisting chiefly of clay
and sand.
=Argillo-calca''reous.= In _agr._, consisting chiefly of clay and chalk.
=AR'GOL.= _Syn._ ARGAL*; TAR'TARUS CRU'DUS, L.; TARTRE BRUT, Fr.;
WEINSTEIN, Ger. Crude bitartrate of potash, as deposited by wine. That
from red wine is RED ARGOL; that from white wine, WHITE ARGOL. See TARTAR.
=ARM'ATURE= (-[)a]-t[=u]re). _Syn._ ARMATU''RA, L. In _magnetism_, a piece
of soft iron used to connect the poles of a horseshoe magnet, for the
purpose of preventing loss of power.
=AR'NICA.= [L., Fr., Eng.] _Syn._ ARNIQUE, Fr.; ARNIKA, WOLVERLEI, Ger. In
_botany_, a genus of plants of the nat. ord. Compositæ (DC.). In the Ph.
U. S., arnica montana (see _below_).
=Arnica Monta'na.= [L.; Linn.] _Syn._ ARNICA, MOUN'TAIN A., M. TOBAC'CO,
GERMAN LEOP'ARD'S BANE; PANACE'A LAPSO''RUM*, L. ARNIQUE, A. DES
MONTAGNES, TABAC DES SAVOYARDS ET DES VOSGES, Fr.; ARNIKA, FALKRAUT, &c.,
Ger. _Hab._ Meadows of the cooler parts of Europe, North America, and
Siberia. It is now cultivated in our gardens. Flowers (ARNICA, Ph. U. S.,
Castr. Ruth., and Bor.) and leaves, diaphoretic, diuretic, stimulant, and
narcotic; in large doses emetic and purgative; root discutient; whole herb
diaphoretic, stimulant, and nervine.
_Prop., &c._ Arnica acts as an energetic stimulant on the cerebro-spinal
system, and as an irritant on the stomach and bowels. It is much employed
on the Continent, and is given in a great variety of diseases--amaurosis,
chlorosis, convulsions, diarrh[oe]a, dysentery, gout, paralysis,
rheumatism, &c. It is much used in Germany, instead of bark, in
intermittents, putrid fevers, and gangrene. In France it is commonly
employed as an excito-tonic in paralysis. It has been greatly extolled, as
a restorative, and in bruises and injuries from falls. The Savoyards and
inhabitants of the Vosges both smoke and 'snuff' the leaves. In England it
is little used except by hom[oe]opaths. It is said that no animal but the
goat will eat this plant. (Thomson.) Its noxious properties chiefly depend
on the presence of cytisine.--_Dose._ Flowers, 5 to 10 gr., in powder,
with syrup or honey; root, 10 to 20 gr. It is most conveniently
administered under the form of infusion or tincture. Severe abdominal
pains and vertigo, and even tetanus and death, have followed excessive
doses.
_Obs._ According to Dupuytren, the emetic action of infusion of arnica
depends on minute particles of the down of the plant which remain
suspended in it, and which may be removed by filtration. See INFUSIONS,
TINCTURES, &c.
=ARNATT'O, Arnott'o.= See ANNOTTA.
=AR'NICINE= (seen). This name has been applied to two substances--the one
discovered by Pfaff; the other by Bastick:--
=Arnicine= (of Pfaff). The resinous matter extracted by alcohol from the
roots and flowers of mountain arnica, and in which their acridity appears
to reside.
=Arnicine= (of Bastick). _Syn._ ARNICI'NA, ARNICI''A (n[=i]sh'-y'[)a]), L.
_Prep._ 1. (Bastick.) From the flowers, by a similar process to that by
which he obtains lobelina. 2. From the flowers (or root), as directed
under ARICINA.
_Prop., &c._ Bitter; acrid; crystallisable scarcely soluble in water;
soluble in alcohol and ether; forms salts with the acids, the
hydrochlorate and one or two others being crystallisable. Its
physiological properties and dose have not as yet been accurately
determined.
=ARO'MA.= [L.] _Syn._ AROME, Fr.; AROM, GERUCHSTOFF, Ger. The
characteristic odour of substances, particularly the peculiar quality of
plants, and of substances derived from them, which constitutes their
fragrance.
=AROMA'TA.= [L.] See AROMATIC.
=AROMAT'IC.= _Syn._ AROMAT'ICUS, L.; AROMATIQUE, Fr.; GEWÜRZHAFT, Ger.
Fragrant; odoriferous; spicy; applied chiefly to plants and their products
(AROMATICS, A. PLANTS; AROMAT'A, AROMAT'ICA, L.; AROMATIQUES, ÉPICES, Fr.;
GEWURZ, Ger.) characterised by their spicy odour or aroma, and warm
pungent flavour, and of which allspice, cinnamon, cloves, lavender,
pepper, rosemary, sage, &c., are well-known examples. They are all
stimulant, carminative, and antiseptic; and from remote antiquity have
been regarded as prophylactic and disinfectant.
=Aromatic.= In _medicine_, _pharmacy_, _perfumery_, &c., applied to
substances, simple or compound, characterised by an agreeable odour or
carminative properties, or both; as aromatic confection, a. pastilles, a.
vinegar, a. bark (CORTEX AROMATICUS, white canella), &c.
=AROMATIC SULPHUR-SOAP= (Ed. Heger). For cleansing the teeth and mouth. A
hard sulphur-coloured soap externally; on cutting, greyish-brown. Composed
of soap with 10 per cent. of hyposulphite of soda, perfumed with a scent
resembling oil of balm. (Hager.)
=AROMATIQUE= (Albin Müller, Brünn). Spirit (90 per cent.), 50 grms.;
sugar, 45 grms.; extractive matter, 4 grms. (composed of cinnamon, cloves,
galangal, zedoary, angelica, anise); water, 81 grms. Sold in
wine-bottle-shaped bottles, and recommended for all derangements of the
digestive organs. (Hager.)
=ARQUEBUSADE'= (ar-ke-b[)o][)o]-zade'). [Fr.] Primarily, the shot of an
arquebuse; but afterwards applied to an aromatic spirit (EAU
D'ARQUEBUSADE, Fr.), originally employed as an application to gunshot
(arquebuse) wounds.
=AR'RACK= (_Syn._ RACK) (arrack'--Brande). [Ind.] _Syn._ ARAC, ARACK,
RACK[double-dagger]§; PALM-SPIRIT; AR'AC'CA, SPIR'ITUS PAL'MÆ, S. SUC'CI
P., S. ORY'ZÆ*, L.; ARACK, Fr.; Arak, Ger. A spirituous liquor imported
from the East Indies. The finer qualities are distilled from the fermented
juice (toddy, palm-wine) of the cocoa-nut tree, palmyra tree, and other
palms; and the other kinds, from the infusion of unhusked rice
(rice-beer), fermented with cocoa-nut or palm-juice, either with or
without the addition of coarse sugar or jaggery.
_Prop., &c._ It is colourless or nearly so, but like other spirit, when
long kept in wood, gradually acquires a slight tinge, similar to that of
old Hollands. The best kinds, when of sufficient age, are pleasant
flavoured, and are probably as wholesome as the other spirits of commerce;
but common arrack has a strong and somewhat nauseous flavour and odour,
depending on the presence of volatile oil derived from the rice, and
corresponding to that of corn-spirit. The inferior qualities are hence
more heating and apt to disagree with the stomach than the other
commercial spirits. In this country it is chiefly used to make punch. When
sliced pine-apples are put into good arrack, and the spirit kept for some
time, it mellows down and acquires a most delicious flavour, and is
thought by many to be then unrivalled for making 'nectarial punch' or
'rack-punch.'
_Obs._ Batavian arrack is most esteemed; then that of Madras; and next
that of China. Others are regarded as inferior. The common par'iah arrack
is generally narcotic, very intoxicating, and unwholesome; being commonly
prepared from coarse jaggery, spoilt toddy, refuse rice, &c., and rendered
more intoxicating by the addition of hemp-leaves, poppy-heads, juice of
stramonium, and other deleterious substances.
=Arrack, Facti''tious.= _Syn._ MOCK AR'RACK, BRIT'ISH A.;
VAUXHALL'NEC'TAR; &c. _Prep._ Good old Jamaica rum (uncoloured), rectified
spirit (54 to 56 o. p.; clean flavoured), and water, of each 1 quart;
flowers of benzoin, 1 dr.; sliced pine-apple, 1/4 oz. (or essence of
pine-apple, 1/2 teaspoonful); digest, with occasional agitation, for a
fortnight; then add of skimmed milk 1 wine-glassful; agitate well for 15
minutes, and in a few days decant the clear portion.
The crude Indian arrack, when subjected to distillation until it has a sp.
gr. ·920, is employed in India, as proof spirit, in the preparation of
official tinctures, and for other pharmaceutical purposes. A very useful
stimulating application, known in India as toddy poultice, and intended as
a substitute for yeast poultice, is prepared by adding freshly drawn toddy
to rice flour, till it has the consistence of a soft poultice, and
subjecting this to heat over a gentle fire, stirring constantly till
fermentation commences.
The light brown cotton-like substance from the outside of the base of the
fronds belonging to the Palmyra palm is employed by the Cyngalese doctors
as a styptic for stopping the hæmorrhage of superficial wounds.
=AR'ROW-ROOT.= The common name of _maran'ta arundina'cea_ (Linn.; _m.
Indi'ca_--Tuss.); a plant of the nat. ord. Marantaceæ (Lindl.;
Cannaceæ--Endl.). It was originally brought from the island of Dominica to
Barbadoes, by Col. James Walker. It has since been extensively cultivated
in the West Indies.
_Tubers_ yield true ARROW-ROOT; when fresh and good they contain about 26%
of starch, of which 23% may be obtained as arrow-root, and the rest by
boiling.
=Arrow-root.= _Syn._ MARAN'TA, AM'YLUM MARAN'TÆ, FÆC'ULA M., L.; RACINE
FLÉCHIÈRE, PIVOT, Fr.; PFEILWURZ, P.-SATZMEHL, Ger. The starch or fecula
obtained from the rhizoma or tubers of _maran'ta arundina'cea_ (Linn.; see
_above_), and which forms the true 'arrow-root' of commerce.
_Prep._ The fecula is extracted from the tubers when they are about 10 or
12 months old, by a process similar to that by which the farina is
obtained from potatoes. In Bermuda the tubers, after being washed, are
deprived of their paper-like scales and every discoloured and defective
part by hand; they are then again washed and drained, and next subjected
to the action of a wheel-rasp, the starch being washed from the comminuted
tubers with rain-water; the milky liquid is passed through a hair sieve,
or a coarse cloth, and allowed to deposit its fecula. This is then allowed
to drain, after which it is again carefully washed with clean water, again
drained, and, after being thoroughly dried in the air or sun, is at once
packed for market. (Cogswell.) In St. Vincent (on the Hopewell Estate), a
cylindrical crushing-mill, tinned-copper washing machines, and
German-silver palettes and shovels are employed; whilst the drying is
effected in extensive sheds, under white gauze, to exclude insects. In
Jamaica the washed tubers are generally pulped in deep wooden mortars;
machinery being seldom employed in any part of the process.
_Prop., &c._ A light, dull, dead-white, tasteless, inodorous powder or
small pulverulent masses, feeling firm to the fingers, and crackling when
pressed or rubbed; viewed by a pocket lens it appears to consist of
glistening particles, which are shown by a microscope to be convex,
irregular, ovoid or truncated granules, most of them, according to Mr
Jackson, being ·0010 of an inch in length, and ·0008 of an inch in
breadth; mixed with others varying from about double to only half that
size. In its action with boiling water, and its general properties it
resembles the other starches; than which, however, it is freer from any
peculiar taste and flavour; and thus agrees better with the delicate
stomachs of invalids and infants than the ordinary farinas.
[Illustration: West Indian Arrowroot (_Maranta Arundinacæa_). Scale
1-1000th of an inch.]
_Comp._ Similar to that of the other starches.
_Pur._ A large portion of the arrow-root of the shops consists either
wholly or in part of the fecula or farina of potatoes or of inferior
starches such as _cacuma_, or East Indian arrow-root, _jatropha_, or
Brazilian arrow-root, _canna_, or _tous les mois_; or is more or less
mixed with sago-meal or rice-meal: such materials can be readily detected
by the microscope. Potato starch is known in commerce as 'FARINA' or
'BRITISH ARROW-ROOT,' or simply 'arrow-root,' whereas genuine arrow-root
is always described as 'Bermuda,' 'St. Vincent,' 'St. Kitts,' or, at
least, as 'West Indian arrow-root.' The substitution of the inferior
farinas for genuine arrow-root is not only fraudulent on account of their
inferior value, but is reprehensible in a hygienic point of view; as some
of them are offensive to a delicate stomach, and exert of themselves, and
still more when carelessly manufactured, a laxative action on the bowels;
whereas the effect of true arrow-root is that of a slight and soothing
tonic.
_Uses, &c._ As an agreeable, non-irritable article of diet for invalids
and children, in the form of cakes, biscuits or puddings, or boiled with
milk or water and flavoured with sugar, spices, lemon-juice, or wine, at
pleasure. For young children a little caraway or cinnamon water is to be
preferred. It is especially useful in irritation or debility of the
stomach, bowels, or urinary organs, and in all cases in which a demulcent
or emollient is indicated. It must not, however, be employed to the entire
exclusion of other food, as, being destitute of the nitrogenous elements
of nutrition, it is incapable alone of supporting life. Arrow-root jelly
is prepared by first rubbing the powder up with a very small quantity of
cold water, and then gradually adding the remainder boiling, stirring well
all the time. Beef tea, veal broth, or milk may be used instead of water.
Some persons boil it for a few minutes. This jelly, flavoured with a
little genuine port wine and nutmeg, is almost a specific in cases of
simple diarrh[oe]a arising from habit or debility.
_Obs._ Arrow-root is imported in tins, barrels, and boxes, from all the
West India Islands; and from Calcutta and Sierra Leone. The best quality
was, until recently, solely obtained from Bermuda; but of late equally
fine samples have been produced on the Hopewell Estate, St Vincent, and,
according to Dr Ure, with the advantage of being prepared with the purest
spring water, in profusion, instead of rain water.
In _commerce_, the word arrow-root is now often loosely used as a generic
term to indicate any white, tasteless, and edible starch or fecula.
=Arrow-root, Brazil'ian.= Cassava-starch or tapioca-meal.
=Arrow-root, East In'dian.= Curcuma starch; from the tubers of the
_curcuma angustifolia_ or narrow-leaved turmeric. The _maranta
arundinacea_ is now also extensively cultivated in India under the name of
maranta Indica, and the fecula therefrom extensively exported, which
might, with equal propriety, be called East Indian arrow-root; but this is
not the case in commerce, the whole passing as W. I. arrow-root
irrespective of the place of its production.
=Arrow-root, Eng'lish.= Potato-starch.
=Arrow-root, Portland.= From the underground tubers of _arum maculatum_
(Linn.) or wake-robin.
=Arrow-root, Tahi'ti.= Tacca starch or Otaheite salep; from the tubers of
_tacca oceanica_.
[Illustration: Rio, or Manihot Arrow Root. Scale 1-1000th of an inch.]
=ARSE''NIATE.= _Syn._ AR'SENATE; ARSE''NIAS, AR'SENAS, L.; ARSÉNIATE, Fr.;
ARSE''NIKSAURE SALZE, Ger. A salt consisting of AsO_{4} and a metal or
other basic radical; _e.g._, ammonio-magnesium arseniate,
NH_{4}Mg_{9}AsO_{4}.
=AR'SENIC= (-se-n[)i]k). As. _Syn._ ARSENIUM; ARSEN'ICUM, ARSE'NIUM, L.;
ARSENIK, A.-METALL, Ger. ARSENICO, Sp., It. The brittle, grey-coloured
metal, or metalloid, which forms the base of the white arsenic and
orpiment of commerce. Discovered by Geber in the eighth century, but first
accurately described by Brandt (A.D. 1773). The poisonous properties of
arsenious acid were not generally known for some centuries after its
discovery. As a medicine it was first employed in intermittents in
Hungary.
_Sources._ Arsenic is peculiar to the mineral kingdom. The metallic
arsenic of commerce is obtained by roasting arsenical pyrites (MISPICKEL),
in earthen tubes, or in tubular earthen retorts; the arsenic sublimes, and
sulphuret of iron remains behind. On the small scale it is prepared by
sublimation from a mixture of arsenious acid and charcoal or black flux.
Combined with oxygen it frequently exists in mineral waters; and, in a
larger quantity, in certain rivulets and streams.
_Prep._ A mixture of arsenious acid, 1 part; and black flux, 2 or 3 parts;
is exposed to a low red heat in a Hessian crucible over which is luted a
deep empty crucible, or an earthen tube, to receive the metal; the latter
being kept as cool as possible. Charcoal or even oil may be substituted
for black flux, and a retort of hard glass may be used, with the same
result. Or the following method may be used:--White oxide of arsenic, of
commerce, 2 dr.; is placed at the sealed end of a hard German-glass tube
(1/2 × 18 inches), and covered with about 8 inches of dry and coarsely
powdered charcoal; the portion of the tube containing the latter is then
raised to a red heat, whilst a few ignited coals are placed beneath the
oxide to effect its slow sublimation. The sublimed metal gradually
attaches itself to the inside of the tube at its cool extremity. A small
charcoal furnace similar to that used for organic analysis should be
employed, and the process conducted under a flue to carry off any fumes
that may escape. The open end of the tube should be loosely closed with a
cork.
_Prop._ Very brittle, so much so that it may be easily powdered in a
mortar; lustre highly metallic; colour steel-grey or bluish-white; texture
crystalline; crystals rhombohedrons; sublimes, without fusion, at 356 to
360° Fahr., (and slowly at lower temperatures), in close vessels
unaltered, but when exposed to the air with conversion into arsenious
acid; at a higher temperature, in open vessels, it burns with a pale-blue
flame. Its vapour or fumes have a characteristic alliaceous odour; it is
slowly oxidised and dissolved by boiling water; but may be preserved
unchanged in pure cold water; it rapidly tarnishes in the air,
particularly when moist, a black film, consisting of metallic arsenic and
arsenious acid forming on its surface; with chlorine, iodine, sulphur, and
hydrogen, it unites to form definite compounds. With oxygen it forms
acids, but no basic oxide. It combines with the metals in a similar manner
to sulphur and phosphorus, the latter of which it resembles in many
respects. These compounds are termed AR'SENIDES, formerly ARSENIURETS. Sp.
gr. 5·7 to 5·9; sp. gr. of vapour, 1·0362.
_Uses, &c._ With copper it forms a white alloy (PACKFONG); and it is added
to some other alloys to increase their whiteness, hardness, and
fusibility. In _medicine_ it is only used in combination. In the metallic
state it is inert; but, from its great affinity for oxygen, it rapidly
becomes oxidised and poisonous; and hence acts as a powerful poison when
swallowed, or when rubbed on the skin. Its fumes are also highly
poisonous. See ARSENIOUS ACID (and _below_).
=Arsenic, Tribro'mide of.= AsBr_{3}. _Syn._ TERBRO'MIDE OF ARSENIC,
SESQUIBRO'MIDE OF A.; ARSEN'ICI BROMI'DUM, L. _Prep._ Add metallic
arsenic, in powder, cautiously and in a very small quantity at a time, to
pure bromine, contained in a vessel set in ice or a freezing mixture,
until light ceases to be emitted; then cautiously distil into a
well-cooled receiver.
_Prop., &c._ Solid below 68° Fahr.; above it, a yellowish fuming liquid,
which boils at 428° Fahr.
=Arsenic, Trichlo''ride of.= AsCl_{3}. _Syn._ CHLO''RIDE OF A., ARSEN'ICI
TERCHLORI'DUM, &c., L. _Prep._ 1. From a mixture of white arsenic, 1 part;
and bichloride of mercury, 6 parts; both in powder, carefully distilled
into a well-cooled receiver.
2. Gently boil powdered white arsenic for some time in hydrochloric acid
to which a little nitric acid has been added; then concentrate cautiously
by evaporation, and distil as before. It is also produced, with the
disengagement of heat and light, when powdered metallic arsenic is thrown
into gaseous chlorine.
_Prop., &c._ A colourless, volatile, highly poisonous liquid, decomposed
by water into arsenious acid and hydrochloric acid. It has been employed
as a caustic in cancer and venereal warts; but its use requires the
greatest caution.
=Arsenic, Flu'oride of.= AsF_{3}. _Syn._ ARSENIC TRIFLUORIDE, TERFLU'ORIDE
OF ARSENIC. A fuming volatile liquid, prepared as the bromide.
=Arsenic, Trii'odide of.= AsI_{3}. _Syn._ TERIODIDE OF ARSENIC, IODIDE OF
ARSENIC; ARSEN'ICI IODI'DUM, A. TERIODI'DUM, L.; ARSENIC IODURE, &c., Fr.
_Prep._ 1. From finely-pulverised metallic arsenic, 2 parts; iodide, 11
parts; mixed and gently heated in a bent glass tube, or a suitable retort,
until combination is complete; the heat being then raised, and the
sublimed iodide collected, and at once put into a well-stopped phial.
2. Arsenic, in fine powder, 1 part; iodine, 5 parts; triturate them
together, place the mixture in a small flask or retort just large enough
to contain it, and apply a gentle heat until liquefaction is complete,
avoiding the formation of iodine vapour; when the odour of iodine is no
longer perceptible, and the mass assumes a reddish-yellow colour and
crystallises on the sides of the vessel, the operation is complete,
without having recourse to sublimation. A very easy and excellent process.
_Prop., &c._ A deep orange-red, crystallisable solid; soluble in water,
and highly volatile and poisonous. Its aqueous solution yields the iodine
unchanged by rapid evaporation, but when slowly concentrated and set
aside, white pearly plates are obtained, consisting of arsenious acid and
the teriodide. As a medicine it combines the properties of both arsenious
acid and iodine, but its use requires great caution. It has been
successfully employed by Dr A. T. Thomson, Biett, and others, in obstinate
skin diseases (lepra, impetigo, herpes, lupus, psoriasis, &c.), and in
real or stimulated cancer.--_Dose_, 1/16 to 1/12 gr. (in pills or
solution), gradually increased to 1/6 or even 1/3 gr. (A. T. Thomson.)
Externally, 2-1/2 gr., to lard 1 oz.; of which 1 dr. may be used at a
time. (Biett.)
=Arsenic, Disulphide of.= As_{2}S_{2}. _Syn._ ARSENIC BISULPHIDE,
BISUL'PHIDE OF A., RED SUL'PHIDE OF A., &c., REALGAR; RÉALGAL, ARSENIC
ROUGE SULFURE, ORPIN ROUGE, &c., Fr.; ROTHES SCHWEFELARSENIK, &c., Ger.
This substance is found native at Solfaterra, near Naples, and in several
other volcanic districts; but that of commerce is often prepared by
distilling arsenical pyrites, or a mixture of sulphur and white arsenic,
&c., in the proper proportions, as noticed under REÄLGAR and RED PIGMENTS.
_Prop., &c._ A fusible, volatile substance; scarlet or ruby-red in mass,
but orange-red in powder, by which it is distinguished from cinnabar;
crystals, oblique rhombic prisms. Sp. gr. 3·3 to 3·6. Its chief use is as
a pigment and in pyrotechny to make white fire. The factitious sulphide
has not the rich colour of the native mineral, whilst it is much more
poisonous. It is improved by re-sublimation.
=Arsenic, Trisul'phide of.= As_{2}S_{3}. _Syn._ TERSUL'PHIDE OF ARSENIC,
YELLOW SUL'PHIDE OF A., SESQUISUL'PHIDE OF A., OR'PIMENT; A.
SESQUISULPHURE'TUM, ORPIMEN'TUM, L.; ORPIMENT, SULFURE JAUNE D'ARSENIC,
&c., Fr.; AURIPIGMENT, OPERMENT, RAUSCHGELB, Ger. This sulphide, like the
last, is found ready formed in nature; and is prepared artificially, by
sublimation, from a mixture of arsenious acid and sulphur, as noticed
under ORPIMENT and YELLOW PIGMENTS. It also falls as a precipitate when a
stream of sulphuretted hydrogen gas is passed through an acid solution of
arsenious acid or of an arsenite.
_Prop., &c._ Golden-yellow crystalline lumps, or a fine golden-yellow
powder; crystals, right rhombic prisms; volatile; fusible; very soluble in
pure alkalies, by which it is distinguished from sulphide of cadmium; and
from trisulphide of antimony by being soluble in hydrochloric acid. The
factitious sulphide (KING'S YELLOW) of the shops often contains 80 to 90%
of white arsenic; and is, therefore, much more poisonous than the native
trisulphide. Sp. gr. (native) 3·44 to 3·60.
_Use, &c._ As a dye, as a pigment, and as an ingredient in fireworks, and
in some depilatories. Silk, woollen, or cotton goods soaked in a solution
of pure orpiment in ammonia, and then suspended in a warm apartment or
stove-room, rapidly lose their ammonia, and become permanently dyed of a
superb yellow colour. The native sulphides (both red and yellow) are much
less soluble, and hence less poisonous, than those prepared artificially.
They also possess the richest colour; and are, therefore, preferred by
artists and dyers. In former times, orpiment, like realgar, was employed
in medicine. See ARSENIC.
=Arsenic, Pentasul'phide of.= As_{2}S_{5}. _Syn._ SULPHARSEN'IC ACID, &c.;
ARSEN'ICI PENTASULPHURE'TUM, &c., L. When a stream of sulphuretted
hydrogen is transmitted for some time through a solution of arsenic acid,
a precipitate of the PENTASULPHIDE is deposited after some hours' repose.
Its formation is accelerated by boiling the liquid.
_Prop., &c._ It greatly resembles the tersulphide in its appearance and
general properties.
=Arsenic, White[double-dagger].= See ARSENIOUS ANHYDRIDE.
=Arsenic, Yell'ow.= Trisulphide of arsenic.
=ARSENIC ACID.= H_{3}AsO_{4}. _Syn._ ACIDUM ARSEN'ICUM, L.; ACIDE
ARSÉNIQUE, Fr.; ARSENICSÄURE, Ger.
_Prep._ 1. Arsenious acid, in fine powder, 2 parts; concentrated nitric
acid, 6 parts; hydrochloric acid, 1 part; mix in a flask or tubulated
retort, and digest, with heat, until solution is complete; after repose,
decant the clear portion and evaporate, to the consistence of a thick
syrup.
2. Dissolve arsenious acid in hot hydrochloric acid, and when the solution
is cold add concentrated nitric acid, in small quantities at a time, until
red vapours cease to be evolved, then proceed as before.
_Prop._ Thick syrup, occasionally forming clear transparent crystals, very
deliquescent, readily soluble in water, and converted by heat into the
anhydrous acid. Extremely poisonous.
=Arseniates.= _Prep._ Most of the metallic arseniates may be formed by
adding a solution of a soluble salt of the metal to another of an alkaline
arseniate, as long as a precipitate falls; which must be collected,
washed, and dried. The alkaline arseniates may be prepared by adding the
base or its carbonate to a solution of the acid, to alkaline reaction, and
then evaporating and crystallising the liquid.
_Prop., &c._ The arseniates of the alkalies are soluble in water; those of
the earths and metals insoluble, except in acids. They are isomorphous
with the corresponding phosphates.
_Tests._ Nitrate of silver added to the solution of an arseniate gives a
highly characteristic reddish-brown precipitate, which distinguishes it
from arsenious acid. Nitrate of lead gives a white precipitate, and the
salts of copper greenish-blue ones. Pure lump-sugar dissolved in an
aqueous solution of this acid becomes, in a few hours, of a reddish
colour, and afterwards of a magnificent purple. Heated with charcoal it
evolves a garlic-like odour, and is reduced to the metallic state. The
suspected liquid being treated with sulphurous acid and boiled for a short
time, the arsenic acid loses oxygen and is converted into arsenious acid,
which may be tested for as such. Sulphuretted hydrogen does not
precipitate a solution of arsenic acid, or an acidified arseniate, until
after the lapse of several hours; and alkaline and neutral solutions not
at all.
=ARSENIC ANHYDRIDE.= As_{2}O_{5}. _Syn._ ANHYDROUS ARSENIC ACID, ARSENIC
ACID; ACIDUM ARSENICUM, L.; ACIDE ARSÉNIQUE, Fr.; ARSENIKSÄURE, Ger. Best
prepared by igniting the arsenic acid, in a platinum crucible, at a low
red heat, as long as water is given off.
_Prop._ White deliquescent substance, and violent poison, readily soluble
in water to the acid.
=ARSENIOUS ACID.= See ARSENIOUS ANHYDRIDE.
=ARSE''NIOUS ANHYDRIDE.= As_{2}O_{3}. _Syn._ AR'SENIOUS ACID, AR'SENIC,
WHITE A.; ACIDE ARSÉNIEUX, ARSENIC BLANC, OXYDE, Fr.; ARSENIGSÄURE,
ARSENICHSTE S., Ger.; ARSENICO BIANCO, It.; A. BLANCO, Sp. The arsenic, or
white arsenic, of the shops.
_Sources._ The white arsenic of commerce is principally imported from
Germany, where it is obtained in the process of roasting arseniuretted
cobalt ores, in making zaffre. At Altenburgh it is procured from arsenical
iron pyrites (mispickel); and at Reichenstein from native arsenide of
iron. About 900 to 1000 tons are also annually collected at Cornwall,
being principally a secondary product of the process of roasting grey
copper ore and white mundic. The British arsenic works in that county are
perhaps the finest in the world. The usual plan is to roast the powdered
ore in muffle-furnaces; by which its arsenic is converted into arsenious
anhydride, which escapes as vapour (smelting-house smoke), and passing
into the condensing-chambers, is deposited in a pulverulent state, forming
the flowers of arsenic, or rough white arsenic, of the smelters, (the
giftmehl or poison-flour of the Germans). The crude article obtained in
this way is purified by re-sublimation in suitable iron pots or other iron
vessels, before it is fit for sale. It then forms a semi-transparent
vitreous cake, which gradually becomes opaque, and of snowy whiteness, by
exposure to the air, and at length acquires a more or less pulverulent
state on the surface.
[Illustration]
In Silesia the crude arsenious anhydride obtained from arsenical pyrites
is refined by sublimation as follows:--For this purpose the cast-iron
vessels (_a_) are employed. Upon these are placed iron rings or collars
(_b_, _c_, _d_) and a hood (_e_), communicating by means of tubes with a
series of chambers, of which the first only is shown in _i_. The flanges
of the cast-iron collars and all other joints having been thoroughly
luted, the fire is lighted and the heat so increased as to cause the
semi-fusion of the arsenious anhydride, which, after cooling, exhibits a
peculiarly porcelain-like appearance, at first being as transparent as
glass.
_Prop._ Crystals (obtained by careful sublimation, or by cooling a boiling
aqueous solution), usually transparent, regular octahedrons (fig. 1), but
sometimes, though rarely, assume the form of tetrahedrons (see 2). When
prepared on the large scale it forms large, glassy, colourless or
yellowish-white, transparent or semi-transparent cakes or porcelain-like
masses (vitreous arsenious anhydride, glacial a. a.), which soon becomes
opaque on their exterior, and often friable and pulverulent; odourless;
volatilises at 380° Fahr.; fumes odourless, unless carbonaceous organic
matter be present, when they smell strongly like garlic; heated under
pressure it liquefies and forms a transparent glass; taste faintly
sweetish, with a slight acidity and astringency, not perceived until some
minutes after being swallowed. The opaque variety is soluble in 80 parts
of water at 59° Fahr., and 7·72 parts of boiling water; but on cooling to
60°, only about one third of this quantity continues in solution. The
transparent variety is soluble in 103 parts of water at 59°, and 9·3 parts
of boiling water. Both soluble in alcohol, syrups, oils, and spirits, and
freely so in alkaline lyes and hydrochloric acid; organic matter generally
impedes its solution; solutions redden litmus; heated with organic matter
it is reduced to the metallic state. Sp. gr. 3·5 (lowest opaque var.) to
3·8 (highest transp. var.).
[Illustration]
=Arsenites.= True arsenious acid (HAsO_{2}) has never been obtained in a
satisfactory condition, but its salts are readily obtained by dissolving
arsenious anhydride in a solution of the base, or by double decomposition.
They are generally white, nearly all insoluble, except those of the
alkalies, and all soluble in acids.
_Tests, Detec., &c._ Owing to the importance of the subject, and for
convenience and facility of reference, the leading tests for the arsenites
and arsenious anhydride are noticed alphabetically below; to which a few
general remarks on their application, under the various circumstances that
occur to the chemist and toxicologist, are appended. When not otherwise
stated, it is to be understood that they are to be applied to pure, or
nearly pure and colourless solutions of arsenious acid or the arsenites.
_Ammonio-nitrate of silver_ gives a well-marked yellow precipitate of
arsenite of silver in an aqueous or arsenious anhydride solution which is
soluble in ammonia and in dilute nitric acid.
_Crystallisation Test._--A very minute quantity of arsenious acid placed
in a small tube (arsenic-tube), and heated in the flame of a spirit lamp,
gives a crystalline sublimate, which collects on the cooler portion of the
tube, and which, when examined by a pocket lens, is found to consist of
sparkling octahedral crystals (see _engr._)
[Illustration: (Magnified.)]
_Ellis's Test._--This is a modification of the 'nascent hydrogen test,' in
which the suspected gas is passed through a tube containing slips of
copper leaf or riband, or still better pure oxide of copper, gently
heated; the end of the tube communicating with the atmosphere being drawn
to a capillary size, at which the gas may be inflamed and tested, as in
'Marsh's Apparatus.' (See _engr._) If arsenic be abundant in the gas, the
copper will be almost instantly covered over with a coating of metallic
arsenic; and after continuing the heat for a few minutes it will present a
beautiful silvery surface, and may then be submitted to further
examination.
[Illustration:
_a_, Flask containing the suspected fluid, dilute sulphuric acid,
and zinc.
_b_, Funnel.
_c_, Tube containing the copper-leaf or c.-riband, and heated by
the lamp _d_.
_e_, Support.
_f_, Capillary end of tube _c_, with the gas inflamed.]
_Lassaigne's Test._ (Adopted by the French Academy.) This consists in
passing the gas generated in the suspected liquid, through a solution of
nitrate of silver. (See _engr._) When arsenic is present black flocculi of
metallic silver are deposited, and arsenious acid remains in solution
mixed with nitric acid and some arsenide of silver. The filtered liquor,
treated with ammonia, will now give a characteristic yellow precipitate of
arsenite of silver; or a little dilute hydrochloric acid may be cautiously
added to precipitate any remaining nitrate of silver, and the liquid,
after filtration, tested for arsenic either in a Marsh's apparatus, or
with any of the liquid tests; or it may be evaporated to dryness, when its
arsenious acid will be converted into arsenic acid by the nitric acid
present, and will then be found to give the usual brick-red precipitate of
arseniate of silver with a solution of the nitrate of that metal. See
MARSH'S TEST.
[Illustration:
_a_, Bottle containing dilute sulphuric acid, zinc, and suspected
fluid.
_b_, Funnel for supplying the bottle with acid.
_c_, _c_, Supports.
_d_, Tube filled with asbestos.
_e_, Bent tube to convey the liberated gas.
_f_, Glass vessel containing a solution of nitrate of silver.]
_Marsh's Test._ Some of the suspected liquid is mixed with dilute
sulphuric acid until strongly acid, and is then poured upon some pure
granulated zinc, or clippings or other small pieces of zinc, previously
placed in the apparatus; hydrogen gas is immediately evolved, and, if
arsenic be present, unites with it, forming arseniuretted hydrogen gas,
which escapes by the aperture _b_ (see _engr._), and may be recognised as
follows:--
It possesses a garlic-like odour.
It burns with a bluish-white flame and emits a whitish smoke.
[Illustration:
_a_, _a_, Bent glass tube, containing dilute sulphuric acid, zinc,
and suspected liquid.
_b_, Stop-cock and jet.
_c_, Plate of glass to receive the stain.
_d_, Support.
_e_, _e_, Bands to keep the tube upright.]
If a piece of window-glass, or a white porcelain plate or saucer, be held
a short distance above the flame, a fine pulverulent film of arsenious
acid is deposited on it. See (fig.) _above_.
If the cold plate be held in the flame, so as to slightly impede the
combustion of the gas, a blackish-brown deposit of metallic arsenic is
obtained, more or less deep, brilliant, and glistening. Both these
deposits may be obtained simultaneously by holding nearly vertically over
the flame a glass tube about 8 or 10 inches long and 3/8ths of an inch in
diameter. See (fig.) _above_.
A solution of arsenious acid may be obtained by letting the flame play
upon 3 or 4 drops of water placed on the under side of the piece of glass
or china, to which the liquid tests may be then applied. Another plan is
to apply drops of the liquid tests to the plate as above, and to let the
flame play on them successively.
The true arsenical spot or film is of a blackish-brown colour, and
generally of a very deep hair-brown, usually surrounded at the
circumference, with a white film of arsenious acid; whilst that of
antimony, which in some points is similar, is of a deep black colour, and
but feebly lustrous, and, when viewed by transmitted light, appears smoky
black; whereas an arsenical spot viewed in the same way appears brown. It
is further distinguished from others by--Treated with concentrated nitric
acid, it instantly disappears, leaving upon the surface of the liquid
traces of the metal, which only dissolve on the application of heat. This
solution, gently and carefully heated, leaves a white residuum, which,
when cold, gives with a concentrated solution of nitrate of silver a
dull-red precipitate of arseniate of silver.--The nitric solution treated
with a few drops of sulphurous acid, and subsequently with sulphuretted
hydrogen, gives a canary-yellow precipitate of trisulphide of arsenic,
which readily redissolves, forming a colourless solution with
ammonia.--The arsenical spot, when heated, is turned bright yellow by
sulphuretted hydrogen, and is then readily dissolved, as before, by
ammonia, and by its bicarbonate; whereas one of antimony is turned of a
deep orange-red, or reddish-brown, by sulphuretted hydrogen, is not
readily dissolved by ammonia, and is scarcely or not at all affected by
bicarbonate of ammonia.--It is freely soluble in and removed by
hypochlorite of soda; a reagent which does not affect antimonial spots.
Heated by a flame of pure hydrogen an arsenical stain rapidly disappears.
A mixed stain of antimony and arsenic does not disappear by the action of
the last two reagents, and is shown to contain arsenic by the two first
tests above. When hydrochloric acid is present zinc stains are sometimes
formed, but they do not resemble those from arsenic. The flame which
produces it is very pale blue or bluish-white; whereas antimoniuretted
hydrogen burns with a pale green or greenish-yellow flame, and a white
smoke, both of which are characteristic.
[Illustration]
_Obs._ Marsh's test is admirable for its simplicity, delicacy, and
trustworthiness, as well as for the ease of its application. It is adapted
to all liquids, whether colourless or coloured, which are not so glutinous
as to inconveniently froth during the extrication of the hydrogen.[79]
Various modifications of the original apparatus have been proposed to
obviate this difficulty; among which the one chiefly deserving notice is
figured in the margin. It consists of a bent tube having two large bulbs
blown in it, and fitted with a stop-cock and jet in the usual manner. In
this case the grains or fragments of zinc are put into the lower bulb
(_a_). It is, however, worthy of remark, that, with ordinary care and
skill, a simple wide-mouthed bottle, furnished with a tube and cock, will
often be found to answer quite as well as more costly apparatus; as the
fluid is less liable to froth than in a narrow tube. Even a common
quinine-phial, or a 4-_oz._ or 6-_oz._ medicine phial, fitted with a piece
of glass tube of very small bore, or even with a piece of a common
tobacco-pipe, for a burner (see _engr._), may be used when no more
convenient instrument is at hand.
[Footnote 79: Animal tissues and liquids containing organic matter are
best prepared for testing for arsenic by Marsh's test, in the following
manner proposed by Odling:--The tissue, or the residue obtained by the
evaporation of a liquid over a water-bath, is to be thoroughly dried at a
temperature of about 212° F., then ground to powder or cut up into small
pieces, next drenched with the strongest hydrochloric acid and allowed to
stand twenty-four hours in a warm place, and finally distilled. The
distillate will contain arsenic (if it existed in the material under
examination) comparatively free from organic matter, and is, therefore, in
a fit state to be introduced into Marsh's apparatus, as the organic
matter, which is the cause of frothing, has been removed.]
[Illustration]
A film of oil placed on the surface of the liquid tends considerably to
lessen the frothing.
_Objec., precau., &c._ Objections have been raised to this mode of
testing, from the great frothing which often occurs with organic mixtures,
and from antimony and imperfectly charred organic matter also forming
crusts somewhat resembling, to the inexperienced eye, those produced by
arsenic. But these objections are invalid, because there are easy means of
purifying the liquid before testing it, and of discriminating between true
arsenical spots or deposits and false ones. Another objection is, that
both zinc and sulphuric acid sometimes contain arsenic; but to obviate
this difficulty, we have only to use them when perfectly pure; and to test
them by means of the apparatus before pouring the suspected liquid into
it. Indeed, these objections apply with equal force to all those tests
which depend on the production of nascent hydrogen. The precaution
necessary to success, and to reliable results, is to set the apparatus
with simple zinc, acid, and water, and after it has worked a short time to
test the evolved gas for arsenic (as above); when, if no trace of that
substance is detected, the suspected fluid, in which the organic matter
(if necessary) has been destroyed by any one of the methods hereinafter
pointed out, may be added, and the operation continued. Care should also
be taken not to light the jet of gas before all the atmospheric air is
expelled from the apparatus, as without this precaution an explosion may
take place.
_Modification of Marsh's Test._--_Davy._ This process consists in the use
of sodium amalgam instead of zinc and sulphuric acid, both of which are
liable to be contaminated with arsenic. Sodium, on the other hand, has
never been found to contain arsenic, and mercury only very rarely; but
should it exist in that metal, it can be easily removed by digesting the
mercury in dilute nitric acid, and afterwards well washing it with water.
One part by weight of sodium to 8 or 10 parts of mercury forms a very good
amalgam. The mercury is placed in a test-tube, and the sodium gradually
added in small portions; the metals readily combine, forming an alloy,
liquid whilst hot, but hard and brittle when cold.
The author uses this amalgam by placing the suspected solution, or solid
substance, along with a little water in a test-tube, then adding a small
piece of amalgam about the size of a grain of wheat, and quickly covering
it with a piece of white filtering paper or the lid of a porcelain
crucible moistened with a dilute solution of silver nitrate slightly
acidified with nitric acid. If arsenic is present, a dull black or deep
brown stain on the paper or porcelain will be developed on the moistened
part, owing to the silver being reduced to the metallic state by the
arseniuretted hydrogen. The solution may be made by dissolving 20 gr. of
nitrate of silver in an ounce of distilled water acidulated with 2 drops
of strong nitric acid.
It is advisable to place between the moistened paper or lid and the tube a
small disc of bibulous paper, to prevent any particles of the liquid
producing minute black spots, and thus interfering with the results.
1/1000th part of a grain of arsenious acid in 1 c. c. of distilled
water gives a very decided effect in a few moments, but much smaller
quantities may be detected, _e.g._, the 1/100000th or even 1/1000000th
part of a grain in 1 c. c.
This method is applicable not only to arsenic as arsenious acid, but also
to other compounds of arsenic, soluble or insoluble in water, _e.g._,
orpiment and realgar, the alkaline arsenates, and even the metal itself if
in powder. Organic matter interferes but very little with this method.
Antimony, as in Marsh's process, will produce, with the sodium amalgam,
results similar to those of arsenic; this, when brought into contact with
the nitrate of silver, forms a black antimonide of that metal.
Fleitmann, however, pointed out that antimoniuretted hydrogen is not
evolved from strongly alkaline solution, and, as in this case, the action
of the sodium amalgam is to render the mixture quickly alkaline, only a
very small quantity of antimony present will be evolved, and by previously
rendering the mixture strongly alkaline the evolution of that gas may be
almost entirely prevented.
It may be occasionally necessary to determine whether the stains on the
paper moistened by the silver solution are due to arsenic or antimony. It
is then best to digest the paper-stain in sulphide of ammonium, the metal
present being converted into a sulphide, and dissolving in the excess of
the alkaline salt, leaving the silver sulphide undissolved; the alkaline
solution when evaporated will, in the case of arsenic, leave a bright
yellow residue, almost insoluble in hydrochloric acid; whereas in the case
of antimony an orange-coloured residue will remain soluble in that acid.
Dr Russell observes that hydrogen alone is capable of reducing silver
solution to the metallic state, but acknowledges that this action is
exceedingly slow. Pellet, on the other hand, maintains that pure hydrogen
when passed through solutions of soda and nitrate of silver has no action
at the ordinary temperature; but he states that the silver salt which has
been fused possesses an alkaline reaction in solution, and hydrogen thus
produces a slight precipitate, which can be prevented by adding a drop or
two of nitric acid.
Davy, however, found in his experiments only the faintest possible effect
of the reducing action of pure hydrogen in solutions of caustic soda and
nitrate of silver.
Finally, the author mentions that where paper is used with the silver
solution we must not forget that the silver alone will after some time
blacken the paper, especially if exposed to light; but this gradual change
is very unlike the quick effect produced by arseniuretted or
antimoniuretted hydrogen. ('Chem. News,' xxxiii, 58-63.)
_Nascent Hydrogen Test._ The apparatus used may be similar to that figured
in the _engr._ The plan followed in the laboratory of Giessen is to heat
the long tube through which the gas passes to redness in several parts, to
produce distinct metallic mirrors; and then to remove the tube from the
hydrogen apparatus and transmit a very feeble stream of dry sulphuretted
hydrogen through it, the metallic mirrors being at the same time heated by
means of a common spirit lamp from the outer towards the inner border or
extremity. If arsenic alone is present, yellow trisulphide of arsenic is
formed within the tube; if antimony alone is present, an orange-red or
black trisulphide of antimony is produced; and if the mirror consists of
both metals, the two sulphides appear side by side, the sulphide of
arsenic, as the more volatile, lying invariably before the sulphide of
antimony. If dry hydrochloric acid gas be now transmitted through the
tube, without application of heat, no alteration will take place if
sulphide of arsenic alone is present, even though the gas be transmitted
through the tube for a considerable time. If sulphide of antimony alone is
present, this will entirely disappear; and if both sulphides are present,
the sulphide of antimony will immediately volatilise, whilst the yellow
sulphide of arsenic will remain. If a small quantity of ammonia be now
introduced into the tube, the sulphide of arsenic is dissolved, and may
thus be readily distinguished from sulphur, which perhaps may have
separated.
[Illustration:
_a_, Flask containing the suspected fluid, dilute sulphuric acid
and zinc.
_b_, Small tube, at the one end having an almost capillary
orifice, where the gas is inflamed.
_c_, Spirit-lamp.
_d_, Support.]
_Reduction Test._ A small quantity of the suspected sample, in the state
of powder, is mixed with twice its weight, or more, of some reducing agent
or flux, and the mixture is placed at the bottom of a very small glass
tube, and heated in the flame of a spirit lamp for some time, when the
arsenic gradually sublimes, and condenses in the cooler portion of the
tube, under the form of a metallic crust, mirror, or ring. A common
test-tube, if of very small diameter, may be employed; but those known as
the reduction tubes of Liebig, Rose, or Berzelius are undoubtedly the most
convenient and efficient. (See _engr._)
Liebig's method is by using a mixture of equal parts of dry carbonate of
sodium and cyanide of potassium. The suspected substance, perfectly
dry and in powder, being first introduced into a Berzelius' tube, is then
covered with 6 times the quantity of this mixture, and so that the whole
will not more than half fill the bulb. A very gentle heat is next applied,
to expel any adhering moisture from the powder and the tube, after which a
strong heat is applied to the bulb, and continued for some time, to effect
the entire reduction and sublimation of the arsenical compound.
[Illustration:
_a_, The arsenical mixture.
_b_, Arsenical ring.]
The best fluxes to use are ferrocyanide of potassium dried at 212° F.,
calcined bitartrate of potassium, cyanide of potassium, and powdered
charcoal.
The metallic ring is proved to be arsenical by the properties and tests
previously noticed. Should it be imperfectly formed, or masked by
decomposed organic matter, the portion of the tube which contains it may
be cut off with a file, next coarsely powdered, then reintroduced into
another arsenic tube, and the exposure to heat repeated.