S O A

SOD

( 333 )

The author adds a few general remarks onthefe combinations. The exprefied oils did notappear to diffolre the compound of oil with limeor alumine. Alcohol diffolves fome of the oleo-metallic compounds without heat, others requireheating;.but in all cafes it diffolves lefs of themthan oil of turpentine does.

Some of thefe were calcined, to determinethe quantity of earth or metallic oxyd left afterthe oil was burnt off, whence fome idea maybe formed of the proportions of ingredients inthefe compounds, taking into account however,that the calcination might carbonate fome ofthe earths, but not all, and that the exad ftateof oxygenation of the metals is not afcertained.Half an ounce, Fr. (288 grs.) of the compoundwith magnefia left 32 grs. which did not effer-vefce: the compound with lime left 36 grs.which effervefced; with clay, 28 grs; with iron,48 grs; with copper, 33 grs; with zinc, 42;with manganefe, 40; with filver, 30 grs. in themetallic ftate; and with tin, as much as 79 grs.of the reduced metal. Whenever thefe combi-nations are to be made, the folutions fhould bein a faturated ftate.

Ammoniacal Soap.

A white faponaceous compound is readilymade by fhaking any oil with liquid ammonia,and this combination is much tifed medicinallyas a ftimulating application; but the unionbetween tire two is much weaker than betweenthe fixed alkalies and oils, fo that this compoundwill not harden, and by keeping for a timethe ingredients partly feparate. A more in-timate union between them is made by addingmuriated ammonia to common foap, as hasbeen already mentioned.

Effintial-Od Soaps. Star ley’s Soap.

The combination of the effential oils withthe fixed alkalies is much more difficult thanthat of the exprefied oils and fats, and muchlefs perfed, fo that a feparation is liable to takeplace whatever pains be taken in the mixture.This kind of foap was firft introduced by analchemift of the name of Starkey, whence it hasL.iken its name. Starkey’s procefs was tediousand uncertain. It confifted in putting in aveffel fome dry carbonat of potafti with oil ofturpentine and fhaking the mixture daily forfix months, during which time part of the oilcombines with the alkali into a faponaceousmafs, and the remainder floats above it unalter-ed. Beaume has taken a good deal of pains tofind out the beft method of making this mixture.Ills method is.the following. 5 I'ut in a marble

mortar, or on a porphyry ftone, any quantity offdry carbonat of potafb, add to it graduallytwice or thrice its weight of oil of turpentine,and rub them together till the mixture has theconfiftence of a foft extrad; then put it into aglafs cucurbit and fet it (at reft) in a dampplace, during which the mixture abforbs muchmoifture from the air, and refolves itfelf intothree portions, the loweft of which is a wateryfolution of the alkali, the middle is the foaprequired, and the upper portion is fome uncom-bined oil of turpentine, generally yellow oramber-colowed. Pour the whole on a ftrainerof double doth, and the foap alone remains onthe ftrainer, which after draining for fome daysmuft be again rubbed in a mortar, and is thencompleat. The alkaline liquor that runs throughthe filter is fomewhat impregnated with the oil.Other recipes have been given for this foap,.the preparation of which lias engaged moreattention, perhaps, than it merits as a medicine, •and which need not be repeated in this place.This foap has an acrid alkaline tafte, and is veryapt to deliquiate on expofure to air.

It does not appear however that the folidcauftic alkalies have ever been ufed for thispurpofe, fo that experiments are ftill wantingto afeertain the precife adion of the alkalies onthe eflential oils.

Acid Soaps.

The ■ combination of acids with oils intofoluble faponaceous fubftances, has already been'noticed under the article Oil.

SOAP , Starkey’s- See the preceding article.

SOAP-LEES. Lixivium faponariwn.

This term has been not unfrequently ufedboth by chemical writers, and alfo familiarly, to-fignify the ley or alkaline lixivium ufed by foap-bcilers. In this country therefore it means avery ftrong folution of potafti, nearly, if notentirely cauftic; but in the countries wherefoda is chiefly ufed by the foap makers, it fig-nifies a ley of cauftic foda. It is therefore anincorred term, and is nearly diiuicd.

The term foap-lees is alfo-employed technicallyby fome to fignify the Jpent ley which is pumpedout of the foap ciftern after the foap has fepa--rated, and being generally more or lefs alkaline,it is never thrown away, but is fometimesufed again in the ftate in which it is obtained,and at other times is evaporated and the refiduecalcined to extrad the alkali.

SODA. Mineral fixed Alkali. Sonde, Fr,.piineralifche yenvachfalkali, Germ.

This alkali is obtained pure from the native

• F.’cuvcns de F!i;vrn*aci€,*