JOURNAL 



O F 



NATURAL PHILOSOPHY/CHEMISTRY, 



AND 



THE ARTS. 



MAT 1800. 



ARTICLE I. 



On the different Effe&s of the Alkalis in the ProduSion of Alum, By Profeffor 



HiLDEBRANDT, of Erlangen*. 



JLT is a known fa£l:, in the ufual preparation or extra£lion of alum, that pot-afli, or urine, 

 is added to the firft folution, which is procured by lixiviating the roafled and weathered 

 aluminous ores. Bergman f, being of opinion that thefc additions tended only to faturate 

 the fuperabundant acid of the lye by which the cryftallization of the fait is impeded, has 

 advifed to add pure aluminous earth, or argil, inftead of the preceding fubftances, on the 

 fuppofition that thofe additions do contaminate the alum with foreign falls ; while, on the 

 contrary, pure alumine would not only faturate the fuperfluous acid, but Increafe the 

 quantity of the fulphate of alumine. Profejfor LampadiusX, who adopted the fame opi- 

 nion, tried by experiments, according to Bergman's idea, whether he could not render 



• Tranflated from Dr. Schercr's (now Profeffor at Halle in Saxony) Chemical Journal, Vol. II. 

 pag. 415. 



t Bergman, de confeSIione atumi/tii, § II. Opufc. Chem. it Phyf. I. Lipf. 17SJ. %'vo. pag. 308. Quura 

 autem aigilla pura bafin aluminis conftituat, excedens lixivii acidum nullo alio modo melius, quam ea 

 donatur, qua: fuperfluum acidum non tantum aufeit, fed etiam falls qusefiti copiara auget. 



J Lampadius, prafl. chemifche Abhandlungen I, Drefden J 795, § 14. 



Vol. IV.— -May 1800. H t^c 



