ARGILLA vitriolata (alum) is ſometimes ſpontaneouſly generated by the decompoſition of pyrites lodged in clay, or in argillaceous ſchiſtus.
It is found in a ſpring at Steckenitz in Bohemia[[33]], in Eaſt Bothnia and elſewhere. What is commonly called plumoſe alum is not a ſaline ſubſtance.
ARGILLA (clay) united to the nitrous, muriatic[[34]], or aerial acids has not to my knowledge hitherto been found in any waters.
METALLIC
SALTS.
The native ſalts belonging to this diviſion, may be diſtinguiſhed by the phlogiſticated alkaly which precipitates them all. The few which have ſaline properties (§ 20.) we ſhall mention here, referring the reſt to the mineralized metals.
CUPRUM vitriolatum (vitriol of copper, blue vitriol) is found in the mines of Herregrund, Fahlune, and others which contain copper pyrites.
FERRUM vitriolatum (vitriol of iron, green vitriol) is formed from the decompoſition of the more common pyrites.