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This preparation is colourless and transparent, With a strongPecntiar, characteristic smeli; it paris With iis ammonia in the form os gas is heated to 13OR, and requires to be heptwith a cautious exclusion os atmospheric air, to the carbonicacia of whicli it readily unites: on this laiter account, the
One has been suggested. Water saturaled with ammonialgas has a less specific gravity than common mater; and the
following useful Table, Jndicative of the quantity of ammonia
SOLUTION OF ACETATE OF AMΜONIA.
Aqua Ammoniae acetatae, P. L. 1787.
I ake of Subcarbona te of Ammonia, tWΟ
Add the acid to the sali untii bubbles of
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Ιf the acid rather predominate, the solution is more grate-ful to the iaste ; and provided that acid be correctly prepared, the proportions here given will be found sufficient: where the strength of the acid cannot be depended upon, it mill beright to be regulated rather by the cessation os emervescenoethan by quantity. Chemicat combinations of the last particles of substances talae place more flowly and dissiculilythan the sirst Whicli unite, and the combination here maynot be complete, especialty goon after the mixture is made ;bui, as it is Stated, the predominance of aikali or acid may beascertained by the alternate Use of turmeric and liimus Paper. The substances, hoWever, With whicli it is usualty administered internalty, are not impatred in their medicat qualities bu a stight excess of acid. The sali cannot be obtained in asotid form Without dissiculty, but it may be crystallised by a cautious sublimation, at a temperature about 25O'; no ad-vantage, hoWeVer, Would be derived Dom sucti a procem forthe purposes of medicine.
Aqua Λmmoniae, P. L. 178I. Spiritus salis ammoniaci, P. L. 1715. P. L. 1720.
Τake of Subcarbonate of Ammonia, s ur
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In the Pharmacopolia of 178I, this solution Was prepared by a distillation os a mixture os muriate os ammonia, subca bonate os potass, 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 be re-tained. The proportion Os the sali is noW reduced to onehalf, as being certainly sussicient to supply a saturaled solution, Whicli is the object intended, With less waste. The solution may also be assisted by a very gentie heat of not more rhan 9O'.
Aqua hali puri, P. L. 1787. Lixivium saponarium, P. L. 1745.
Boiling distilled Water, a gallon. Dissolve the sub carbonate of potass in tWopinis of the water. Add the remaining Water
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AL ALIES AND THEIR SALI S. io the lime . Mix tho liquors while they a rehoi, Stir them together, then set the mixture by in a covered vesset, and after it has cooLed, Strain the Solution through a Cotton ling. Is any dilui ed acid di opped into the solution occasion the OX trication of bubbles of gas, it Will be necessary to adit more limeand to stra in il again.
A pint of this solution ought to Weigh
When subcarbonate os potass and lime are thus mixed, the Iime unites to the carbonic acid and fornas an insolubie cambonate of lime, and the potass remains in solution. The proportion os lime noW directed, is, is it be good, sussicient 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, by capillary attraction, a considerable quantity of the solution os
potass, but this maybe disiodged, is it be thought necessary, by cautiousty pouring Upon the Suriace an equat quantity of Water, Which being lighter than the solution itself, Will notinix with it untii the greater part of the lalter has passed thesilier. This inconvenience is, however, considerably diminisbed by the present process, in Whicli the proportion oflimo is diminished one half from the former. At every period of the process, the preserace of external air should heavoided, as affording a supply of carbonic acid; and calico, as here directed, both fillers more quickly than any other
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means, and is not acted Upon by the potass. The purity of the solution should always be tried by the addition os limeWater, Whicli, is there be any combined carbonic acid, will denote it by a precipitate. It is also possibie that a superabundarice of lime maybe used, and that lime and potass may both be dissolved; this is discoverable and removeable in the fame way, by dropping in the solution os subcarbonate os potass. This solution is more dense than water, and has
SOLUTION OF SUBCARBONATE OF POTASS.
Aqua ali praeparati, P. L. II87. Lixivium tartari, P. L. 1745. Oleum tartari per deliquium, P. L. I 20.
Dissolve the subcarbonate os potass in the Water, and then Strain the solution through
This is a more definite preparation than the aqua hali praeparati of the Pharmacopoeia os II 8 I, Which Was prepared by exposure of the sali to a moist atmosphere, that it might
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attract Water, and deliquesce, and it also differs frona it: sor, during the exposure necessary sor deliquescence in the lat-ter, carbonic acid as weli as moistUre Was attracted froni thoair. The solution here directed Will, in the ordinary state of the subcarbonate, amount to nearly eighteen ounces in bulla. It wili facilitate the solution is the water be warm, towhich there is no objection; and , as the liquor will usuallycontain sonae insolubie matter, the liquor may either be sil- tered, or the sediment be allowed to subside, and the clear
Cata cum hali puro, P. L. II 87. Causticum commune fortius, P. L. II 45.
This mechanical admixture forms the caustic most commonly employed, and whicli is more convenient and manage- able in iis operation than the potass alone. The lime giVes
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consistence to the solution os potass, and this consistence, asit prevenis the potass Dom spreading, regulates the boundaries of iis action on the part lo Whicli it is applied.
Kali purum, P. L. IT 87. Lapis infernalis sive septicus, P. L. 1720.
Tahe of Solution of ΡOta SS, a gallon. Evaporate the water in a Clean iron potoVer the sire, uniit, When the ebullition has CeaSed, the potass rem nins in a state of fu- Sion ; Potir it upon a Clean iron plate, intopieces of convenient sol m.
This preparation is sussiciently pure for tis Use as a cautery, much more indeed so than the former hali purum ; it cannot be obtainest in a state pure enoUgh for accurate experiments excepi by a solution os it in alkohol, separation of the undissolved salis, and a second evaporation, according tOBerthollet's process Iurn. si P . V. xxvira.). The ceSSation os ebullition is suffcient proos that the water is evaporaled, and it may, When potared upon the iron plate, be re dily divided, be re it seis, into smali pieces of convenient Si Ze, or run into moulds of the shape it may be wished togive it. Is heated to 360' it fuses, and again concretes as it
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cools; it destroys animal matter rapidly, and is applied as a caustic. It deliquesces on expostare, and should there re becarefulty hept in stopped botiles, and one part of water WilIdissolve two of it. The establishment of the compound nature os potass and soda, and of sonae of the earths by Davy Phil. Trans. I 808), is not applicabie to iis medicat use. Potass however consislsos a peculiar metat, named by him Potassium 86, and Oxygen l4 in I OO.
Q Tali aeetatum, P. L. 1787. Sal diureticus, P. L. I 45.
In the former Pharmacopoeia no directions Were given foe
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the crystalligation of this sali, but meret y that iis solution Should be evaporated to dryness. The crystalliged sali is hoWever a more elegant and laniform preparation, and it is usualty found in the shops, as it is made by some chemisis upona large scale; it requires only to be fused to assume this appearance. The great potnt of attention necessary in iis preparation is, that the heat be never sussicient to decomposeor char the vegetable acid. Iis crystalliZation depends tiponthe liquefaction of the dry sali by heat, and the assumptionos a regular form as it coois, rather than on separation Domiis solution in water. From iis foliat ed appearance it hasbeen called Terra foliata Tartari , when nearly saturaled ithecomes brownish ; and during the evaporation, either Domthe mucilaginous matter carried over by the acid in distillation, or the decomposition os a portion of the acid, carbonaceous matter is deposited; the second siliration removes this. The evaporation is to be continued in a heat which should not bemuch greater than 2l2', untii a drop taken on a glass rodseis very quickly ; and When cold feeis dry and pulverable ;when the heat is to he removed, and it is to be allowed tocool very gradually. It has also been named Sal Sennerti, inhonour of Senneri, whom Boerhaave supposes to have been iis inventor ; and Sal diureticus, Dom iis supposed effecisupon the kidneys, and in faci no sali has at different times been designated by such a number of names, such for instanceare Magisterium Purgans Tartari, Sal essentiale Vini, and Oleum Tartari Sennerti. Lowitz has advised generally, that colouring matters should be separated from saline substances, by an admixture of them with freshly burni and poWdered. Charcoal, and, aS the practice ansWers, it may be occasionalty
useful to employ it in this preparation. Acetate os potass is Whi te, Shining, and united into a mass os large Plates, Whicli deliquesce in the ala, and should there re be hept in melis topped botiles. Water at 60' dissolves rather more than an
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equat Weight, and iis solution in Water ought to be complete. It is solubie in Dur times iis weight of aikohol. In the Present preparation the athali rather predominates, for thesali, as it is found in the shops in iis foliaten form, affecisthe colour os turmeric paper, but it is not in an unpleasant degree. Ιf the salt be coloured, it is said that it may beasterWards rendered colourless by fusion, Solution in Water, filiration, and evaporation ; and that in this process carboneis separated and collected on the sitire. Dr. Higgins states the composition of this sali to be 38,5 acid, 61,5 potassin 100 paris cHiggins, on Acelous Aci . There is also amemoir of Μ. Cadet upon the preparation of this sali, i Mem. de PA demis, &c. t. 1, p. 518), who recommendS aS th surest method of obtaining large crystals, that the lalter part of the evaporation Should be carried on in a Water bath.