jJr-.-:rt-;*-.:-»i)' .vJ/t >j/ ■■^'iic ay-^- C-.srr. - 25,'? 



ductive. The zinc obtained from China, vmdcr the name 

 of tufniu-go, is confidcreJ to be purer than the German, and 

 tlicrefore a fmall ditfcrence is obierved in their fpeeific gra- 

 vities. 



The properties of zinc feparatcd from its ore, and puri- 

 fied, are, that it fcarccly undergoes any variation in atmo- 

 fpheric air or in water ; and that, by the addition of copper, 

 in different proportions, you obtain brafs, pinchbeck, prince's 

 metal, Manhcim gold, &c. All acids deprive it of its in- 

 flammable matter, and dillblvc it with effervefcence. With 

 the vitriolic acid it gives a cryftallinc fait, which is fulphat 

 of zinc, or, as it is commonly called, white vitriol. That 

 white vitriol which is obtained not in a cryftalline form, but 

 in white malfes like refined lugar, contains often a mixture 

 of foreign metallic particles, fuch as iron, copper, and lead; 

 but it may be purified by adding to a fokition of it pure zinc, 

 by v.hich the above metals will be precipitated : if the fo- 

 kition be then filtered, and expofed to cryftallife, you will 

 obtain pvire white vitriol. 



By the nitrous acid, zinc is diflblved with a ftrong effer- 

 vefcence and in great quantity producing cryftals : if you 

 poLir alcohol over thefe and diftil them, you will obtain very 

 good edulcorated fpirit of nitre. It diffolves alfo in the mu- 

 riatic acid, and emits a ftrong ofi'enfive vapour; this clear fo- 

 lution faturated cannot be brought to flioot into cryftals : if 

 you reduce it by evaporation to a gelatinous mafs, and place 

 It in a retort over the fire, you obtain, in the fame manner 

 as when you dillil zinc with fal-animoniae and corrofive 

 fublimate, butter of zinc of a fomewhal thick confidence. 



It is foluble alfo in aqua-regia, and by that acid gives a 

 triple neutral fait, in the fame manner as fal-ammoniac. It 

 dillblves likeuil'e in concentrated acetous acid, and flioots in- 

 to cryftals: the remaining acids, viz. offparry fluor, arfenic, 

 borax, fugar, tartar, forrcl, citrons, ant?, phofphorus, and 

 fat, excrcife an adion over zinc alio. The alcaline folvents 

 do the fame ; and the proccfs fuccecds beft with a concen- 

 trated 



