_Prop., &c._ A white or greyish-white mass, or acicular crystals
(according to the mode of its preparation); very soluble in water and in
alcohol; and decomposed by exposure to the air. It has been highly
recommended as an alterative, resolvent, and liquefacient, particularly in
scrofula, glandular swellings, chronic inflammations, and the other
affections in which chloride of barium and iodine are given.--_Dose_,
1/12th to 1/8th gr. (gradually and cautiously increased to 1 gr.), in
distilled water, 2 or 3 times a day. Externally, as an ointment (3 or 4
gr., to lard, 1 oz.), as an application to scrofulous swellings. (Biett.)
It possesses all the irritant, corrosive, and poisonous properties of the
chloride, but in a much more violent degree.
=Barium, Nitrate of.= Ba(NO_{3})_{2}. _Syn._ NITRATE OF BARYTA; BARY'TÆ
NI'TRAS, L. _Prep._ As the acetate or chloride of barium, substituting
pure nitric acid for acetic or hydrochloric acid.
_Prop., &c._ Transparent, colourless octahedrons, which are anhydrous,
insoluble in alcohol, and require about 8 parts of cold water, and about 3
parts of boiling water, for solution.
_Uses._ In _chemistry_, to prepare baryta, and as a test for sulphuric
acid and the soluble sulphates; and in _pyrotechny_, to give a green tinge
to flame.
=Barium, Oxalate of.= BaC_{2}O_{4}. _Syn._ OX'ALATE OF BARYTA; BARY'TÆ
OX'ALAS, L. _Prep._ By precipitating a barium salt with oxalate of
ammonium. Very nearly insoluble.
=Barium, Oxide of.= BaO. _Syn._ BARYTA, BARY'TES, CAU'STIC BARYTA*, OX'IDE
OF BA''RIUM, PROTOX'IDE OF B., HEAV'Y EARTH; BARYTE, OXIDE DE BARIUM,
TERRE PESANTE[dagger], &c., Fr.; BARYT, BARYTERDE, SCHWERERDE, &c., Ger.
One of the earths discovered by Scheele in 1774.
_Sources._ Sulphate and carbonate of barium are abundant minerals, forming
the 'vein-stone' of many lead mines. It is from the latter that baryta
and the barium salts are almost exclusively obtained.
_Prep._ 1. A mixture of carbonate of barium and charcoal (both in fine
powder and moistened) is strongly ignited, for some time, in a porcelain,
Hessian, or black-lead crucible, and then allowed to cool out of contact
with the air, from which it must also be subsequently carefully preserved.
2. (Pure.) Crystallised nitrate of barium is calcined in a capacious
covered porcelain or Hessian crucible, at a bright red heat, until red
(nitrous) vapours are no longer disengaged, even on raising the
temperature; and the residuum, as soon as the temperature has fallen
sufficiently, but whilst still warm, is at once transferred to a bottle,
as before.
3. M. Rosenthiel's process is founded upon the decomposition of sulphide
of barium dissolved in boiling water by oxide of zinc. Caustic baryta and
sulphate of zinc are formed.
_Prop._ A greyish-white, spongy, earthy-looking mass, fusible only before
the oxyhydrogen blowpipe; highly caustic, corrosive, and alkaline, and
slaking, like quick-lime, on the addition of water, but with the evolution
of more heat.
=Barium, Peroxide of.= BaO_{2}. _Syn._ DEUTOX'IDE OF BARIUM; BA''RII
BINOX'YDUM, &c. L.; BINOXIDE DE BARYUM, &c., Fr. _Prep._ Pure baryta is
heated to full redness in a porcelain tube, and a stream of pure dry
oxygen passed over it as long as the gas is absorbed.
Baryta, 4 parts, is heated as above in a platinum crucible, and chlorate
of potassium, 1 part, gradually added to it; the chloride of potassium
formed along with the binoxide being afterwards washed away with cold
water.
_Prop., &c._ Grey or greyish-white; with water it forms a hydrate, which
is slightly soluble in water, and undecomposed by it in the cold. It is
interesting chiefly in its relations with peroxide of hydrogen and the
oxygenised acids of M. Thénard.
=Barium, Phosphate of.= Ba(PO_{4})_{2}. _Prep._ In a similar manner to the
oxalate, which it resembles in being an almost insoluble white powder.
=Barium, Sulphate of.= BaSO_{4}. _Syn._ SULPHATE OF BARYTA, HEAV'Y SPAR,
BOLO''GNIAN S., CAWK (mi); BARY'TÆ SUL'PHAS (Ph. E. & D.), SPA'THIUM
PONDERO'SUM, &c., L.; SULFATE DE BARYTE, SPATH PESANT, &c., Fr.;
SCHWEFELSAURES BARYT, SCHWERSPATH, &c., Ger. This salt is found native,
often in beautiful tabular crystals, but more frequently in white or
reddish-white masses. It is also occasionally prepared artificially, as a
pigment and chemical, by decomposing a solution of chloride of barium with
dilute sulphuric acid, or with a solution of sulphate of sodium; the
resulting precipitate being collected, well washed, and dried.
=Prop., &c.= When pure, or free from iron, its powder is white. It is
insoluble in water, and nearly insoluble in all other menstrua; before the
blowpipe it decrepitates, fuses with great difficulty (by which it is
distinguished from the sulphates of strontium and calcium), and ultimately
melts into a hard, white enamel. Mixed with charcoal, and heated to
redness in a covered crucible, it is reduced to sulphide of barium. It is
readily decomposed by fusion with alkaline carbonates; also very slightly
so by their cold solutions; but ultimately completely, though slowly, by
their boiling solutions. Sp. gr. 4·3 to 4·75.
_Uses._ Chiefly as a pigment (PER'MANENT WHITE), and to adulterate
white-lead; for which purposes the native sulphate is commonly well
washed, first in very dilute sulphuric acid, and afterwards in pure water,
to remove any iron which may contaminate it, and impair its whiteness. It
is also used to form sulphide of barium; and, in _pyrotechny_, instead of
the more expensive nitrate.
=Barium, Sulphide of.= BaS. _Syn._ SUL'PHIDE OF BARIUM, SUL'PHURET OF
BARYTA; BA''RII SULPHURE'TUM, &c., L.; SULFURE DE BARYUM, &c., Fr. _Prep._
Sulphate of barium, well dried and in fine powder, 3 parts; powdered
charcoal or powdered coal, 1 part; the mixture is pressed tightly into an
earthen crucible, and the cover being fitted on, it is exposed for 1-1/2
to 2 hours, to a bright red heat; after it has cooled, the black mass thus
obtained is powdered, and boiled in water, and the resulting solution
allowed to crystallise. Some authorities recommend forming the mixed
powders into a stiff paste with oil, or oil of turpentine, before
calcination; but this is not at all necessary.
_Prop., Uses, &c._ Crystals, thin and nearly colourless plates, containing
combined water; very soluble in hot water, less so in cold water; and
rapidly decomposed by exposure to the air. It is principally used to form
the BARIUM SALTS, and in organic analysis. Care should be taken in its
preparation to expose the solution to the air as little as possible.
SULPHIDES of a higher grade may be formed by boiling this compound with
sulphur; but they possess little practical interest.
=Barium, Sulphite of.= BaSO_{3}. _Syn._ SUL'PHITE OF BARYTA. _Prep._ By
testing a soluble barium salt with sodium sulphite, and washing the
precipitate. Insoluble.
=Barium, Tartrate of.= BaC_{4}H_{4}O_{6}. _Syn._ TAR'TRATE OF BARYTA.
_Prep._ Like that of oxalate of barium. White powder. Slightly soluble.
=BARK.= [Eng., Dan.] _Syn._ COR'TEX, L.; ÉCORCE, Fr.; BAUMRINDE, RINDE,
Ger. The rind or exterior covering of vegetables, corresponding to the
skin of animals. It consists of the--cu'ticle or epiderm'is--cellular
substance, containing colouring matter, &c., and--li'ber, the inner or
true bark. The last is formed of woody fibre in great quantity, intermixed
with cellular tissue. At the commencement of the annual growth of a tree,
the bark separates spontaneously from the wood, in order to make room for
the new matter forming beneath. It thus increases by yearly layers, and
gradually perishes on the outside, owing to distension, from the growth of
the interior portion. Its physiological uses are numerous and important.
It is the depository of many of the secretions of plants, and it acts as a
living filter, separating secretions from each other, and allowing a part
of them to pass off horizontally through the medullary processes on their
way to the centre of the tree. But its principal offices appear to be to
act as a protection to the tender wood, and as a channel for the sap in
its descent from the leaves. "True bark only exists in exogens and
gymnosperms; in endogens its place is supplied by cortical integuments,
which cannot be separated from the adjacent wood, without violence."
(Lindley.)
According to Liebig, the characteristic ingredients found in bark are
excrementitious--"substances evidently expelled by the living organism."
True wood yields only ·25% to 2% of ash; whilst the bark of some trees
give 6, 10, to 15 times more; and these, like the organic constituents,
differ materially in their composition and characters.
The uses of different species of bark in medicine and the arts are well
known. CINCHONA-BARK is invaluable in fevers; OAK-BARK furnishes the
tanner with one of the most important materials of his trade; and the
tenacious fibres of other varieties are manufactured into cordage and
textile fabrics.
Barks should be collected at that season in which they can be most easily
separated from the wood, which, with a few exceptions, is late in the
spring; because at this time the active principles deposited in their
cells are most abundant. OAK-BARK, collected in spring, contains four
times as much astringent matter as that collected in winter.
=Bark.= (In _medicine_.) See CINCHONA.
=Bark.= (In _tanning_.) See OAK.
=Bark, Jes'uit's.= Cinchona-bark.
=Bark, Salt of= (Essential). See EXTRACTS and SALTS.
=BAR'LEY.= _Syn._ HOR'DEUM, L.; ORGE, Fr.; GERSTE, Ger., Anglo-S. A
well-known grain, the produce of several species of the genus _hordeum_.
_Var., Cult., &c._ Those principally cultivated in England
are--TWO'-ROWED, LONG'-EARED, or COMM'ON BARLEY (_hor'deum dis'tichon_,
Linn.); SPRING'-BARLEY, SQUARE'-B., or BERE (_h. vulga''re_, Linn.); and
SIX'-ROWED BARLEY, WINTER B., Scotch BERE or BIGG (_h. hexas'tichon_,
Linn.). PUT'NEY, SPRAT, or BATT'LEDORE B. (_h. zeocriton_, Linn.), is
another species less frequently met with. Of each of the above there are
several varieties. In Spain and Sicily, two crops of barley are obtained
in a year; but, in countries so far north as Britain, it produces only
one, and is a delicate species of grain. In England it is generally
adopted as a succession crop on light lands, following turnips or green
crops. (Loudon.) The 'yield' per acre varies from 28 to 64 bushels, and is
usually from 28 to 40 bushels. The average weight per bushel is 50 to 51
_lbs._; but the best Norfolk and Essex samples weigh 53 to 54 _lbs._ per
bushel.
_Comp._ The leading constituents of barley are nearly similar to those of
wheat, but it is scarcely so rich in nitrogenised matter. According to
Einhof, the ripe SEEDS or GRAINS are composed of--
Meal 70·05
Husk 18·75
Moisture 11·20
------
100·