ANT

ANT

( 85 )

tates from it a fulphated oxyd of antimony,leaving the tartar nearly pure: the alkalies,both the caullic and carbonated, effeft only apartial decompofition, a loofe white oxyd beingprecipitated by the firft, and by the fecond, acarbonated oxyd, which, after a time, cryftal-lizes in the form of divergent rays. If eithertartareous acid, or tartrite of potafli, is added tothe folution of antimoniated tartar, previoufly topouring in the alkali, there will be no precipi-tate, for the tartrite of potafli, produced by theaddition of the alkali, immediately redifl'olvesthe antimonial oxyd. A Ample folution ofemetic tartar is for the fame reafon incapable ofbeing totally decompofed by any quantity ofalkali, and hence probably have arifen the greatfeeming differences in the conllituent parts of thisfait, according as it has been analyfed by meansof a pure alkali, a carbonated alkali, or otherreagents. According to Thenard 1 the purecryftals of emetic tartar, from whatever anti-monial oxyd they have been prepared, andwhatever has been the proportion of ingredientsemployed, contain, in a given weight, precifelythe fame quantity of antimony, of tartareousacid, of potafh and water, and even the degreeof oxydation of the metal is alfo invariable.His method of analyfing this fait is firft toafcertain its water of cryftallization, by dryingin a heat juft not fufficient to decompofe it;fecondly, to diffolve the emetic tartar, andprecipitate the antimony by fulphuretted hydro-gen ; thirdly, to afcertain the tartareous acid bythe addition of acetite of lead, as long as anyprecipitate is produced ; and laftly, to deter-mine the quantity of potafli, by igniting therefidue, and extracting the alkali by dilutednitric acid. By a very careful analyfls, con-ducted according to the above method, M.Thenard found too parts of emetic tartar tocontain 38 oxyd of antimony,

34 tartareous acid,

16 potalh,

8 water,

96 c

4 lofs

100

but the tartareous acidulum, which fuppliesboth the acid and alkali to the emetic tartar,contains 57 tartareous acid, 33 potafh, andabout 10 water and lofs; or 70 tartrite of pot-afh, and ao tartareous acid, in excefs ; hence

it follows that the mother water remainingfrom the preparation of emetic tartar, con-tains an antimoniated tartrite of potalh, whichfait is neceffarily mixed with the former, whenprepared by evaporation to drynefs, inftead ofcryftallization, and muft, no doubt, in fomedegree modify its effeft upon the conftitution,producing variations which are unjuftly attri-buted to the pure emetic tartar.

Oxalic acid, by digeftion with oxyd of anti-mony, takes up a confiderable proportion, andthe liquor depofits on evaporation, oxalat ofantimony in fmall cryftalline grains. Thisfait is fparingly foluble either in water or wine*The latter preparation has an emetic quality,and has been ufed in medicine, inftead of thecommon antimonial wine. Acetite of antimonyis prepared in the fame way with the foregoingfait: it forms minute cryftals, and was one ofthe firft antimonial falts that was ufed in medi-cine on account of its emetic quality: it wasfirft adminiftered by Angelo Sala , but is nowwholly fuperfeded by the antimoniated tartar.

Of the neutral falts there are only three, theaft ion of which on antimony has been muchnoticed, namely, the fulphat, oxymuriat, andnitrat of potafh.

Sulphat of potafh (and probably fulphat offoda) is decompofable by antimony in the dryway. This faft was firft noticed by Monnethe fufed in a crucible two parts of fulphatedpotafh, mixed with one of pulverized antimony,and obtained a yellow, cauftic, femivitrified mafsof antimoniated fulphuret of potafh, which, whenwafhed with hot water, was partially foluble inthat fluid, and, as it cooled, was precipitated inthe form of kermes, or hydro-fulphurettedoxyd of antimony. The metal therefore wasoxydated at the expence of the fulphuric acid,and the fulphuret of potafh refulting from thisdecompofition, united with the metallic oxyd,rendering it foluble in water.

Oxymuriat of potafli afts with great energy onantimony, as indeed it does on all the eafily com-buftible metals. If equal parts of this fait, andof antimony previoufly reduced to a fine powder,,are mixed together, and ftruck brifkly on ananvil, a remarkably loud detonation takes place;if the mixture, inftead of being ftruck, is pouredinto fulphuric acid, or rather if fulphuric acidis poured upon the powder, a hiding noife isproduced, red fparks are emitted, and the metalis converted into an oxyd.

Nitre and antimony in equal parts, or twoparts of the former to one of die latter, being

*Ann. de Chinn*