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put fome of the juice in a glafs, and add afolution of acetite of lead. This will produce acopious white fediment in any cafe ; afterwhich add fome drops of ftrong nitric acid. Ifthe juice contained no fulphuric acid the whiteprecipitate will be rediflolved, and the liquorbecome again clear, the citrat of lead and malat(of which a fmall portion will alfo be formed)being readily foluble in nitric acid, but if thejuice was mixed with fulphuric acid the fulphatof lead will remain at the bottom. If this iscollected, wafhed, and dried, the quantity offulphuric acid may be eftimated from the knownproportions of this fait. See Lead.

Pure citric acid cryftallizes according toLowitz 1 in alum-fhaped cryftal's, confiding oftwo 4-fided pyramids joined bafe to bafe, or,fometimes, according to Dize, in rhomboidalprifms. Its tafte is intenfely four, and, whendiluted, very grateful to the palate. It is veryfoluble in water, one ounce of diddled water ata moderate heat diflolving ounce of the crys-tallized acid, and producing 30 degrees of coldby the mixture. In a boiling heat water diffolvestwice its weight of the acid. The crydals arenot deliquefcent. Diddled per fe the productsare an empyreumatic acid phlegm, carburettedhydrogen gas, and carbonic acid. It feems tobe compofed of carbon and hydrogen withoxygen in unknown proportions.

If this acid is boiled with a fmall portion ofnitric acid, much nitrous gas is given out, andthe liquor evaporated and cryftallized yieldsfome oxalic acid. A greater proportion ofnitric acid converts the whole into acetous acid,as it appears, without palling through the inter-mediate date of the oxalic. Thus Wedrumbobtained half a dram of oxalic acid from onedram of citric acid with 200 grains of the nitric:with 300 grains only £ of a dram j and with600 grains not an atom.

Vauquelin aflerts that this acid maybe ob-tained by palTing oxymuriatic acid gas throughgum arabic in water for a confiderable time.™

The culinary ufes of lemon juice are wellknown. The concrete citric acid may be oftenfubdituted for the juice with advantage wherethe latter is not conveniently procurable, but itis to be obferved that none of the peculiar fla-vour of the fruit fo agreeable in the frefli lemonpaffes into the folid acid, which is merely four,and without any particular adringency.

The u f e to which this acid has lately beenput in manufafture is as a dfcharger of colourin calico-printing: the white figured parts of

1 Grcn’s Handb.

coloured patterns prepared with iron colour*being produced with great clearnefs and effectby this acid. It is not abfolutely neceflary tocrydallize the acid for this purpofe but only toconcentrate it. The mineral acids anfwerequally as difchargers, but when diffidentlydrong to do this effectually, they injure thetexture of the cotton.

Citrats . Of the falts formed by this acidwith alkaline, earthy, and metallic bafes, only afew deferve particular mention.

Citrat of Potafj. This has long been knownmerely as a mixture in medicine under the nameRiverius’s fait. About 12 to 16 parts of lemonjuice will faturate one of common carbonat ofpotaffi. To prepare it more accurately accord-ing to Vauquelin,* 36 parts of the crydallizedacid diffolved in water, require for faturation61 parts of crydallized carbonat of potadi.This fait crydallizes, though with difficulty,and is very deliquefcent: 100 parts containabout 55.5 of acid, and 44.5 of alkali. It isdecompofed by barytes and lime..

Citrat of Soda. This is a very foluble cryf-tallizable fait. According to Vauquelin, 36parts of acid require 42 of dry carbonat of foda,fo that 100 parts of the citrat of foda confifls of60.7 of citric acid, and 39.3 of foda.

Citrat of Ammonia. Thirty-fix parts of citricacid faturate 44 of carbonat of ammonia. Hence100 parts of the fait contain 6 2 of acid, and38 of ammonia. It is with difficulty cryflal-lized, and is very foluble.

Citrat of Barytes . A hundred parts of thisfait confids of equal weights of citric acid andbarytes. When barytic water is poured intocitric acid, diffolved in water, a precipitate isformed, which immediately is rediflolved. Butwhen approaching the point of faturation thebarytic citrat is depofited in quantity, at firftpulverulent, afterwards in fine cludered cryflal-line needles.

Citrat of Magnefia.. Thirty-fix parts of theacid require for faturation 40 parts of carbonatof magnefia,. and' 100 parts of the fait contain-33.34 of magnefia, and 66.66 of acid. Thisis not crydallizable, but when nearly evapo-rated to drynefs, the fait rifes in muffiroom-likeknobs, white and opaque.

Citrat of Lime. This is the bed known ofthe earthy citrats, being formed, as alreadymentioned, in the preparation of the citric acid.It is but fparingly foluble in pure water, andthe folution has very little taffe. But an ex-cels of acid renders it extremely foluble, 10a

* Ann. Chim. tom 6,