1520 SALTS. 71. Alumen. 



71, ALUMEN. Of a iV.'eetiih and very ailringent 

 taftc: its watery folution made turbid by foda, 

 but not by pruffiate of lime: tumefying and 

 lofing its tranfpaiency when expofed to heat, 

 and becoming a fpongy mafs after lofing its 

 water of cryftallization. 



phosphoreum Flying to pieces v/hen expofed to a violent heat, confiding 



of phofphorio acid and alumina. 



Grenat de Valence. Prouft chem, ann, \.% p. 196. 



Phcfphat df Alumina, Tho?nfan chem. 2, p. '3,6'^. 



Found in Valentia: a tallelefs powder, not ioiuble in WPter: 

 yields a gritty powder when diiTojved in phofphcric ncid, 

 and a gummy lolution which is converted by heat into a 

 tranfparent glafs. It does not feem to belong to this genus. 



muriatkunu Expofed to a violent heat, or moiflened with ftrong ful- 

 phuric acid, emitting acrid grey vapours of a difagree- 

 able odour. 

 Found in Tufcanyy efilorcfcing on the furface of aluminous foils 

 like powder, in dry feafons, alfo in the n\ouths of cu'es and 

 fiffures of rocks with the appearance of wool or a white crult; 

 its tafte is rather bitter than aftringent. 



»ati%>um. Pure, dry, not emitting vapours when fulphuric acid is 

 poured on it. 

 Al'jmen ni^dum. Syft. ?/^/. xii. 3. /. loi. «. i. 

 Alumen nativum. iValLjyst. 2. ^.32. « i. 

 Alum. Kirnvan 2. p. \ ^, Schmeifser mn. I . p. 270. 

 Alum. Ihom/on chem, 2. ^. 364. 



1. In the form of an efflorefcent powder. 



2. Of a common form, folid, without luHre. 



3. In a ftalaftitical form., folid, withput luHre. ■ 



4. Solid, of a filky lullre, fibrous internally. 



5. Cryftallized in a double 4 lided pyramid. 



Found in Egypt, the i (lands of the Archiprlago^ Mahay Sicily^ in 

 the craiers of volcanos. the alps of SifJitx^erla^id and the lakes 

 of Tujcan)\ and in various parts of Europe in aluminous fliill: : 

 it is diflblved in 34 times its weight of cold water, and t:i{i\y 

 forms cryftals which efflorefce a little in the air: when ex- 

 pofed to a ftrong heat it fublimes, fwells, foams, lofes its 

 tranfparency, and ^t lall lofes 44 per cent, of it, weight : its 

 folution always turns vegetable blues red: fpeciiic gravity 

 1,7109. contains fulphate of alumina 49. fulphstc of polafs 

 7. water 44. Fauquelin: 



