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Was attracted Dom the air. The solution here directed will, in the ordinary state of the subcarbonate, amount to nearly eighteen ounces in bulla.
Boi ling distilled Water, a gallon.
Dissolve ille sub carbonate os potass int vo pinis of the water. Add the remaining water to the lime. Mix tho liquors Whilethey are hol, stir them together, then set themixture by in a Covered vesset, and after ithas cooled, stra in the solution through a cotton bag. I f any diluted acid dropped in to the solution occusion the extrication of hubbles of gas, it Will be necessary to add more limeand to stratri it agnin . A pint of this solution ought to M eigh
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lisne unites to ilie carbonic acid aud sornas an insolubie carbonate of limo, and the potass remains in solution. The Proportion os lime here directed, is, is it be good, sum cient for the perfect decomposition of the sali, and there is an ad-vantage in not having a greater residuary mass than is necessary. The precipitate os carbonate of lime retains, bycapillary attraction, nearly j of the solution of potass, but1his may be disiodged by cautiousty pouring iapon the sur- face an equat quantity of water, Whicli heiag lightor than thesolution itself, ill not mix Vith it untii the greater part of the lalter has passed the filier. At every period of the process, the presence of external air should be avoided, as afford- ing a supply of carbonic acid; and calico, as here directed, both filers more qui chly than any other means, and is notacted upon by the potass. The puri ty of the solution should almys be tmed by the addition os lime Water, Whicli, is therebe any combined carbonic acid, wili denote it by a precipitate. It is also possibio that a superabundarice of lime may have been used, and that lime and potass may both be dissolved; this is discoverable and removabie in the fame Way, by drop-Ping in the solution os subcarbonate os potass. I his solu
Tali purum, P. L. t 78I. Lapis infernalis sive septicus, P. L. t 7 20.
Tahe of Solution of Potas S, a gallon. Evaporate the Water in a Clean iron potover the sire, uiatil, When the ebullition has
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CCased, the potaSs rem ius in a stetito os fu- Sion: pour it tapon a Clean iron plate, intopieces of Convenient forna.
This preparation is sussiciently pure for iis uis as a caute , much more indeed so than the former hali purum; itcannot be obtained in a state pure enough for accurate ex periments excepi by a solution of it in alkohol, separationof the undissolved salta, and a second evaporation, accordingto Berthollet's process Durn. si P . V. xxviii.). The ceS- sation os ebullition is sufficient proos that the Water is eu Poraled, and it may, When poured upon the iron plate, bereadi ly divided, he re it seis, into smali pie os of convenient siZe, or run into moulds of the shape it may be xvished togive it. Ιf heated it fuses, and again concretes as it cools; it destroys animal matter rapidly, and is applied as a caustic. It deliquesces on exposure, and one part of water Uilt dissolve two of it.
Calx eum hali puro, P. L. 178I. Causticum commune sortius, P. L 17Φ5.
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This mechanical admixture serms the caustic most commonly employed, Whicli is more convenient and managestis in iis operation than the pota alone. The lime gives consisterice to the solution os potass, and this consistence, as it Prevenis the potass Dom sprea ling, regulates the boundaries of iis action on the part to whicli it is applied.
Natron tartarigatum, P. L. 1787
This sali cons sis of tartaric acid, soda and potass, thesoda combining Witti the superabundant ac id of the supersali: it is cheresere a triplo sali, and it has been judged more convenient here and in some other instances to e pressinis differetice by tbe adjective tartaricasa, chan to introduce
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the three mords necessary to iis description. Iis crystals aveprisms of eight or ten uraequat sides, having their en is truncated at right angies. It is solubie like tartrate os potasS, iis taste is bitter, and it emoresces on exposure to air. VaU- quelin states, that it consists of tartrate of potass 5s, tartrate of soda 66. It has been called sali of Seignette froin iis inventor, and also Sal Rupellensis, or Rochelle saltu No distinction was made, P. L. II 45, between the salis Prepared by adding soda or potass to the super-sali, and both vere Eept indiscriminalew under the name of solubie tartar. In this, as in the sulphate os potass and many other salis, aflight excess of altati disposes the crystals to forin more rea lily, and renders them more perfeci in their forna.
Natron vitriolatum, P. L. II 87. Sal catharticus Glauberi, P. L. IT 45.
Tahe of the Sult Whicli rem alias a ter thedistillation os muriatic acid,
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This preparation depends upora the fame principies asthos e tapon wllicli the sulphate os potass is formed; but soda disters frona potass in iis relation to sulphuric acid, and does not strictly unite ivitii it into a super-sest; as, hoWever, more than half their weight of water enter into the composition of the crystals of sulphate of soda, is that water be acidit will influence the character of the sali, and heiace iis saturation with aikali is as necessary here as in the former instance. Iis crystals are si x ided pristias terminated by tWo-sidod pyramids, but they are most commonly irregular and channelledon their fides. One part is solubie in sonae liat less than three of water at 6OV, and in less than iis own bulla at 2l2'. I irwangives iis proportions as acid 23, 52, SOda J8,18, Water 58. 00. I f heated, it melis Dona the agency of iis Water of crystalligation, and when this is evaporaled, it may be fused by an increase of the heat. Aster this toss of water, Lirinan states la to consist os ac id 56, soda 44. In France it has been prepared by disturbing iis more regular crystalligation bystirring ; when it talios a stilay spicular forna, and has been called improperly Sal d 'Epsom. It will be observed, thathesides this process sor iis formation. sulphure of soda stands asan article in the catalogue of Materia Medica. The quantityobtained, by the pharmaceutic process for supplying muriaticac id, is not sufficient for the consumption; and there re itlias been jud ged right to admit it also frona the manufa turei S, Who prepare large quantities, especialty in the works for muriate of ammonia, Where they obtain a very impure carbonato os ammonia in thei viret distillation os bones, and separate iti se impurities by sulphuric acid; they astor ad ,
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employ a doubie decomposition, mixing the sulphate of mmonia Cith muriat eos soda; Dom this fhey sublime themuriate os ammonia When the sulphate of soda rem ains, Whicli, is it be crystalli et ed, is sussiciently pure and very che3P.
Natron praeparatum, P. L. 1787.
Boi ling distilled Water, a gnilon. Eoil the soda in the water ser half an hour,
and strain the solution ; letit evaporate to tW opinis, and be set by, that CryStal S may forrn. Thro v a Way the rem aining Solutiora.
Ali barilla or heip contains much heterogeneous matter, and the Spanish, Whicli is the purest, is to be preferred. It is prepared by the incineration os marine planis of varioussoris, and is also found native in some paris of Africa. Water dissolves the subcarbonates and other salis, of Whicli, contrary to What happens with the subcarbonate os potass, the subcarbonate of soda crystalliZes sirst after due evaporation; the sirst crop yielded wili, there re, be sussiciently pure, and of their regular form: in the second crop, the crystalswill contain a largor proportion of the other most predominant sali, the sulphate of soda, and approximate to iis formos crystal; only the first, theresere, is on this account directed to he Eept for use, and the residuarV or mollier liquors to be ilirown aWay. Iis crystals are formed of two
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Tahe of Sub carbona te of Soda, a Pound . Apply a genti e lient to the soda in a Cleantron vesset untii it be comes perfectly dry, and at the sanie time constantly stir it withara iron rod. La Stly, reduce it into P Oxv d Cr.
The crystals of subcarbonate of soda, is exposed to air, Jose a part of their water, and efforesce or nil into powde . ΙΙenco, the proportion os soda contained in the sali hept intliti inops becomes indefinite. In thissest completely essioresced, the proportion of Water lost may be ne arly one-half of the whole. By a definite expostare to heat the whole water may beevaporaled, and the sali thus prepared is more useful and uniform in many of iis applications. Care must be taken that the heat be not urged too far, for a red heat deprives it also os iis carbonic acid. Dried subcarbonate of soda contains, according to Κirwara, carbonic acid 4O,04, soda 59,86; and J00 paris of the crystals are deprived of their 61 of Wator.
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CARBONATE OF SODA. I ake of Sub carbonate of Soda, a PΟUnd. Sub carbonate of Ammonia, three
Distilled Water, a Pint. Having previ ousty dissolved the soda in
the water, add the ammonia, then by means of a sand bath apply a hent of i8o' for three. hours, or untii the ammonia be dri ven ossi Lastly, set the Solution by to crystallige. Therem aining solution may in the sume mann erhe evaporaled, and set by that crystals may again forna.
This sali bears to iis subcarbonate the fame relation that carbonate os potass does to iis subcarbonate ; it is prepared in the fame WaV, possesses the fame comparative adVantages and contains double the quantity of carbonic acid. M roth gives as iis proportions, acid 39, soda 38, Water 23.
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The crystals of alum contain of water, and when it is exposed to heat it melis and the water evaporates aWari, thisis the oldect of the present preparation, Whicli is intendedfor external use. It should be remembered in prepa ingit, that a violent heat will decompose the sali and drive ostibe greater part of the acid also.