Cooley's Cyclopaedia of Practical Receipts Volume I Part 73

_Prop., &c._ Crystals, flat, four-sided tables, colourless and transparent; sometimes double eight-sided pyramids; slightly efflorescent in dry warm air, but otherwise permanent; decrepitate when heated, and lose their water of crystallisation; fuse at a red heat; volatilise at a white heat; insoluble in hydrochloric acid and in alcohol, slightly soluble in rectified spirit, and very soluble in water; water at 60 dissolves 43-1/2% of the crystals, and nearly 37% of the dry salt; and when boiling 75% of the former, and about 66% of the latter; a saturated boiling solution (223 Fahr.) contains 100 parts of water, and 78 parts of the crystallised salt.

The crystals contain 2 atoms of water; and a formula of BaCl_{2} + 2Aq.

_Uses, Phys. eff., &c._ In _chemistry_, it is employed as a test for sulphuric acid and the soluble sulphates. In _medicine_, it has been employed, both internally and externally, as an alterative, resolvent, and deobstruent, in scrofula, glandular swellings, and enlargements, scirrhous cancer, skin diseases, &c.; and more particularly in the first with marked benefit. In large doses it is poisonous. According to Sir B.

Brodie, its action on animals is a.n.a.logous to that of a.r.s.enic. Locally, it acts as an irritant. A very weak solution, used as a lotion, often proves serviceable in herpetic eruptions, and as a collyrium in scrofulous ophthalmia. _Dose_, 1/2 gr. thrice a day, in water, gradually increased to 2 or 3 gr.

=Barium, Chlorate of.= Ba(ClO_{3})_{2}. _Syn._ CHLORATE OF BARY'TA; BARY'Tae CHLO"RAS, L. _Prep._ From a solution of chloric acid neutralised with freshly precipitated carbonate of barium; the resulting solution, after filtration, being crystallised by evaporation.

By pa.s.sing chlorine through strong milk of hydrate or of carbonate of barium, in the same way as in making chlorate of pota.s.sium.

_Prop., &c._ Soluble in 4 parts of cold water. Used in pyrotechny, and to make chloric acid.

=Barium, Ferrocy'anide of.= Ba_{2}FeC_{6}N_{6}. _Syn._ BA"RII FERROCYANI'DUM, L. From pure ferrocyanide of iron digested in baryta water. By careful evaporation, efflorescent prismatic crystals may be obtained, soluble in 4-1/2 parts of water.

=Barium, Fluoride of.= BaF_{2}. _Syn._ BA"RII FLUORI'DUM, &c., L. A white powder, formed by digesting freshly precipitated carbonate of barium in hydrofluoric acid, in excess.

=Barium, Hydrate of.= Ba(HO)_{2}. _Syn._ HYDRATE OF BARYTA; BARYTae HYDRAS, L. _Prep._ By digesting caustic baryta, or barium oxide, with a little water, or igniting gently the crystallised hydrate. It can be obtained crystallised as follows:

1. From a concentrated solution of either nitrate or chloride of barium, precipitated with a rather strong solution of pure pota.s.sa, or of pure soda, perfectly free from carbonic acid.

2. A strong solution of sulphide of barium is boiled with successive portions of black oxide of copper, until it ceases to give a black precipitate with a salt of lead; the liquid, after filtration, yields crystals of the hydrate on cooling.

=Prop., Uses, &c.= Forms a bulky white powder, containing 10-1/2% of water of hydration, which it retains even after ignition. In this state it is soluble in 20 parts of cold water, and in 2 parts of boiling water. The hot saturated solution, as it cools, deposits abundantly columnar crystals (CRYS'TALLISED HYDRATE OF B.), which contain 51-1/2% of water, of which they lose, by drying and ignition, 88-3/4% (= 4-3/4% of their weight), being reduced to the state of the common or amorphous hydrate. Of all the bases it has the strongest affinity for both sulphuric and carbonic acid, and hence its solution (BARY'TA-WATER) and those of its neutral salts (nitrate or chloride) form our most sensitive tests for these substances.

Sp. gr. 43 to 47. The crystallised hydrate is converted into the ordinary hydrate at a gentle heat, and this last fuses at a low red heat without losing its water of hydration, which it only slowly and with difficulty begins to part with at higher temperatures. In _chemistry_, its uses are, for the most part, similar to those of BARIUM, OXIDE OF.

=Barium, Iodide of.= Ba_{2}I. _Syn._ BA"RII IODI'DUM, L.; IODURE DE BARYUM, &c., Fr.

_Prep._ 1. Dissolve sulphide of barium in water, and add iodine (gradually) in excess; after the reaction is complete, filter, and either evaporate to dryness, or crystallise.

2. Digest freshly precipitated carbonate of barium, in excess, in a hot solution of protiodide of iron; filter and evaporate to dryness; then re-dissolve and crystallise.

3. By saturating hydriodic acid with oxide or carbonate of barium.

_Prop., &c._ A white or greyish-white ma.s.s, 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'Tae NI'TRAS, L. _Prep._ As the acetate or chloride of barium, subst.i.tuting 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'Tae 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, &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 ma.s.s, 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 pa.s.sed over it as long as the gas is absorbed.

Baryta, 4 parts, is heated as above in a platinum crucible, and chlorate of pota.s.sium, 1 part, gradually added to it; the chloride of pota.s.sium 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. Thenard.

=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., c.a.w.k (mi); BARY'Tae 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 ma.s.ses. 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. 43 to 475.

_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 ma.s.s 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 princ.i.p.ally used to form the BARIUM SALTS, and in organic a.n.a.lysis. 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.; eCORCE, 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 quant.i.ty, 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 pa.s.s off horizontally through the medullary processes on their way to the centre of the tree. But its princ.i.p.al 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 excrement.i.tious--"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 const.i.tuents, 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_.