ayb On the Tartareius Sails. 



arrd £lwr. In oT(3er to prepare them he makes ufe of difi%«tTt ffictliods, according to the 

 nature of the thetal. Thofe which have the property of decompofing water, can be em- 

 pWydd in the metalli-c ftate, others in the ftate of oxide, and fome diffolved in the acids. 



Z'mc and iron are iu the nrft clafs— copper, tin, and lead in the fecond — ^mercury and 

 filver in the third. 



The alkaline tartrites of manganefe, of iron, of zinc, and of tin, are very foluble, and 

 difficuhly cryftallizable. Their tafte participates more or lefs of the metallic oxides which 

 diey contain. None of them is decompofed, or at leaft precipitated, either by cauftic 

 aHcali, or the alkaline carbonates ; but they are all decompofed by fulphurated hidrogen, 

 hidro-fulphuret, and the gallic acid. There is however an exception with regard to the 

 farit of manganefe and fulphurated hidrogen. 



The alkaline tartrite of copper is diftinguiflied from the other tartrites by its faccharine 

 tafte, and the great quantity of metal it contains. That of lead is not foluble. It is not 

 decompofed by the alkalis, and what is remarkable, it is not decompofible even by the 

 futph^ites. 



The tartrites of pot-afh and of filver, of pot-afli, and of mercury, do not follow the ge- 

 neral rule; they are decompofed by the alkalies, the alkaline carbonates, fulphurated hi- 

 drogen, the hidro-fulphurates, the fulphafes, and the muriates. 



Though tartar emetic, or antimoniated tartarite of pot-afh, has long been a fubje£l: of 

 inquiry by many chemifts, and a number of interefling properties have been difccvered in 

 confequence, Citizen Thenard direfled by new ideas, has made fome additional difcove- 

 ries. He fliews for example, that a folution of this fait, which is decompofed and preci- 

 pitated 'by the alkalies and tlie carbonates, cea(fes to be decompofed if a fufhcient quantity 

 of tartrite of pot-afh be added, in order that this fait 'may retain the oxide of antimr;ny in 

 folution. 



It likewife entered into the plan of thisohemlft, to fubrhit the tartar emetic to a more 

 accurate analyfis than has hitherto been made, and this atiellyns has required that of various 

 other falts, particularly the nitrate of pot-afh or falt-petre, the proportions of the elements 

 of which effentially intereft many of the arts. 



In order to obtain this refult, he expofcd loo parts of cryftallifed tranfparent emetic 

 tartar to a gentle heat, in order to drive off merely the water of cryftallization. It was 

 reduced by this operation to 92 parts. After having diflblved thefe 92 parts in water, he 

 precipitated them by fulphurated hidrogeri, which afforded 50 parts of golden fulphuret, in 

 which there arc, according to other experiments before made by him, 38 parts of Oxide of 

 antimony, fuch as it cxifts in the emetic tartar. In order to afcerfaiti the quantity of tar- 

 tarebus acid, he mixed the acetite of lead with fuperabundance of acid, in the liquOr fepa- 

 rated from the golden fulphur, and he obtained one hundred parts of tartrite of lead, 

 which contain, according to his analyfis, 66 parts of oxide of lead, and 3^ of tartareous 

 acid. 



Having 



