Mr. Hatchett’s Analysis of 
290 
lead. The lead was therefore precipitated by sulphuric acid, 
and afterwards the molybdaena by prussiate of pot-ash. 
A drachm of the ore was digested with muriatic acid, and 
was completely dissolved, excepting a small residuum of sili- 
ceous earth. The solution was transparent, and ivithout co- 
lour. In the course of some time it plentifully deposited crys- 
tals of muriated lead. When these crystals were separated, 
the solution was evaporated, and the interior of the bason was, 
during the evaporation, covered with a bluish saline crust, 
which dissolved and the colour disappeared when the vessel 
was shaken. The concentrated solution decanted from the 
muriate of lead (which had been precipitated during the eva- 
poration) was of a deep blue, which disappeared when water 
was added. The solution was then saturated with alkali, and 
deposited a white precipitate, which consisted of molybdic 
acid, together with a small quantity of oxyde of lead. 
According to these experiments Mr. Klaproth remarks, 
that the yellow sparry lead ore of Carinthia is composed of 
oxyde of lead and molybdic acid, and that this mineralogical 
novelty is the more remarkable, as it is the only one of the 
kind known at present. It is also worthy of notice, that the 
molybdaena changes its form according to the method em- 
ployed to precipitate it from alkaline solutions ; for it is ob- 
tained either in a crystalline form, or in that of a white powder, 
or in that of a citron-coloured oxyde. When crystallized, it is 
soluble in acids, and in water ; as a white powder it does not 
dissolve in water, unless a small quantity of muriatic acid is 
added ; but in the state of the citron-coloured oxyde, it is in- 
soluble in water as well as in the acids. Mr. Klaproth 
considers that this difference is occasioned by the presence of 
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