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ceases to give out heat on the farther addition of water. This mixture Will be more conveniently made and iis dose more eastly apportioned than that os the sormer Pharma
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Ammonia praeparata, Sal cornu ceris, P. L. I 787. Sal volatilis salis ammoniaci, P. L. II45. Sal volatilis, P. L. 1720.
In this process a doubie decomposition tines place, and tWo neW compounds, carbonate os ammonia and muriate oflime, are Di med. To effect this, a high temperature, as here expressed, becomes requisito, and the employment also os asultable additional apparatus hept at a loW one for the collection and condensation of the sublimed sali, for whichpurpose a Wide mouthed glass retori and receiver Will ansWer, care being taken that it is never completely closed. Davystates the relatiVe proportions os constituent paris of the
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ALKALIES AND THEIR SALTS. Icompounds of carbonic acid and ammonia, to vary accord- ing to the temperature employedt, in loW ones there sis more acid and water, in high ones more alliati. Bergiangives the proportions as carbonic acid 45, ammonia 43, Water I 2 ; and as thus prepared it is, in faci, a Subcarbonate os ammonia. When sublimed, it forms a calae of striaten crystalline appearance, smelling strongly of ammonia; Whenheated it melas Dom the presence of Water, dries as this evaporates, and at last sublimes entirely away unaltered. Two paris of cold water dissolve one of this sali, bolling water dissolves more than iis Weight. In the former Pharmacopoeia, the Same Salt Was also prepared by distillation froni bones, purified by repeated sublimation Dom chaia, and kept under the nanae of Sal Cornu
sOLUTION OF ACETATE OF AMMONIA.
Aqua ammoniae acetatae, P. L. IIS T.
Tahe of Carbona te of Ammonia tivo
Is the acid rather predominate, the solution is more grate fui to the taste; and provided that acid be correctly prepared, ille proportions here given will be found sussicient: Where
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the acid cannot be depended upon, it mill be right to he regulated rather by the cessation os effervescence than by quantity. The sali cannot be obtained in a solid serm without difficulty, but it may be crystalliged by a cautious sublimation, at a temperature about 250' ; no a luantage however Would bederived Dom sucti a process for the purposes of medicine.
Tahe of Carbo nate of Ammon in eight
Distilled water a Pint. Dissolve the Subcarbonate os ammonia in the water, aud sit ter the solution throughpa Per.
In the formor Pharmacopoeia this solution Was prepared by a distillation of a mixture os muriate os ammonia, subcarbonate os potasti, and water; but the result is so nearly the same When the present formula is used, that there seemed tobe no good reason Why a more complex process Should berulamed.
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Aquae ammoniae purae, P. L. 1787.
I like of Muri te of Ammonia. Lime ne vly prepared, of each two Vater a pirat and linis. Reduce the muriate of ammonia and theli me into poWder separalely, then mix them, and introduce them into a large gla88 retori, into Whicb a pint of the ater has been previOUSty potared. Ηaving placed the retori in v sand bath, lute on a tubulated receivor, through whicli the ammonia may passinio a third vesset containing half a pint of the water, and cool . Then ut si St apply agentie heat, and increase it by degrues uritil
It must be carefulty remembered, that liquor ammoniae of the present Pharmacopoeia, corresponds With aqua ammoniae purae, and not with aqua ammonia of the former. Great care and attention are necessary in every part of this Process; ta
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the two salis axe to be poWdered separalely before they aromi Xed, for is they be trituraled together, ammonia will be extricaled, Which should be prevented untii the means for iis collection are adopted. The salts are to be shaken weli to-gether, rather than rubbed, and added to the water in theretori; the coid produced by the solution of the salt willcounieraci the heat produced by the staking of the lime, anda charge so made ivili be manageable untii the receiver is fitted on, and the heat of the sand bath applied; this heat neest not be greater than 300', and should be very cautiousty and stoWly raised, to prevent the rapid ebullition and expansionduring the extrication Dom gas of a charge of such density; and for the fame reason a large retori is directed. The ammonia rises immediately in the form of gas, and a portion of the water is there re placed in a siluation to condense it; in the subsequent stages Water Will arise Dom the charge in theretort. The third vesset directed in the formula, may beeither a common botile fitting moderately, for no great pressure is necessary, to a straight iube issuing Dona thebottom .of the receiver, and dipping below the sursace of the water it contains, or Woulse's apparatus may be used; butwith moderate attention the simpler means Will ansWer bellerperii aps than the more compleX. This process is, I belleve, osten performed upon a largo scale in an iron retori, which does no injury to the preparation, Whilst a glass one Willos course be brohen. In either case the receiving botile must be kept cold by Wet cloths or ice, for the lo ver thotemperature of the water the greater quantity of ammonialgas Will it condense, and the condensation is accompani ed by an increase of iis heat. Is two botiles, each containing half the quantity of Watex directed, be used, they Will bo most manageable, as they maybe changed alternately, so as to pre-vent ei ther stom being overtieated, and the contents of both
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may be mixed together at last. This preparation is colou less and transparent, With a strong peculiari characteristic sineti ; it paris With iis ammonia in the form of gas is healedio 130', and requires to be hept with a cautious exclusion ofatmospheric air, With the carbonic acid of whicli it readilyunites: on this laiter account the propriety of keeping it insmali botiles instead os a large one has been suggested. Water saturaled with ammonial gas has a less specific gravity than common mater; and the following useful Table, indicative of the quantity of ammonia contained in solutions according totheir specific gravity, is taken Dom Μr. Davy. Sp. Gr.
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ALKALIES AND TFIEIR SALTA. Over ille sire, a id gradu atly as much more a Ce-tic acid as may be necessary for perfeci Saturation. Let the solution be fui ther reduceti toone-half by evaporation, and stra in it: then hymenns of a Water balli evaporate it, so thaton being romoved froni the fire it shali crystallige.
In the former Pharmacopoeia no directions mere given forthoe crystalligation of this sali, but merely that iis solutionshould be evaporated to dryness. It is however a more elegant and uniform preparation, and as it is made by some chemisis upon a large scale, it is usualty found in the shops; andit requires only the fusion of the sali to give it this appearance; the great potnt of attention necessary is, that the heat be neversussicient to decompose or char the vegetable acid. Ιis crystalligation depends upon the liquefaction of the dry sali byheat, and the assumptiora os a regular form as it coois ratherthan ora the separation froni iis solution in mater. From iis foliated appearance it has been called Terra foliata Tartari; ithas also been named Sal Sennerti, in honour of Senneri, Whom Boerhaave supposes to have been iis inventor. Lowitzhas advised generally, that colouring matters should be separated Dom saline substances, by an admixture of them With Deshly burni and poWdered charcoal, and, as the practice an-swers, it may be occasionalty useful to employ it in this preparation. The sali is White, shining, and the mass formed oflarge platea, Whicli deliquesce in the air. Water at 60' dissolves an equat weight. It is solubio in Dur times iis weightos aikohol. In the present preparation the aikali rather pre- dominates, but not in an unpleasant degree. Is the sali be
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coloured, it is salit that it may be rendered colourless by Κ-sion, solution in Water, sitration, and evaporation ; and that in this process carbone is separated and collected on the filier.
Mili vitriolatum, P. L. I 78I. Tartarum vitriolatum, P. L. II 15. Tartarum vitriolatum, P. L. II20.
Tahe of the Salt whicli rema ins after thedistillation os Nitrio Acid two
Boiling Water tWo gallonS. Mix them that the sali may be dissolved, neXt adii as naucti sub carbonate of potastias may be requisite for the saturation of the acid. Then boli the solution untii a pellicleuPPCar Upon the sui face, and , after Strainingit, set it by that crystals may forna. Hau ingpoured aWay the water, dry the crystal S Uponbibulous Paper.
This salt was prepared formerly by exposui e of the residue aster the distillation os nitric acid, to a violent and long-continued heat so as to drive ossilie superabundant sulph ic acid i
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than whicli the present mode is more manageable and convenientia The concretion of the sali in the common process osten
I his sali is the immediate residue aster the distillation os nitric acid, sirst dissolved and then crystalliged; in iis coaxsc