/ 
the Carinthian Molybdate of Lead. 205 
EXPERIMENT II. 
A. Twenty grains of the purified ore were boiled with 
four ounces of a lixivium of carbonate of pot-ash. When all 
the water was evaporated, there remained a white saline mass, 
which was reduced to powder, and treated with distilled water 
as in the former experiment. 
A large quantity of a heavy white residuum remained on 
the filter. 
The clear solution was saturated as before with sulphuric 
acid, and a white precipitate, similar to that of the former ex- 
periment, was obtained. This was separated, and a copious 
precipitate of molybdaena was produced, upon the addition of 
prussiate of pot-ash. 
B. The white residuum was then edulcorated, and when 
diluted nitric acid was poured on it, it was dissolved with ef- 
fervescence. From this solution I precipitated the lead by 
sulphuric acid, and afterwards the iron by prussiate of pot- 
ash. 
Ammoniac, when digested on the ore, had not any effect. 
From these experiments it appears, that the molybdate of 
lead is decomposed by the fixed alkalies in the humid way, 
and that the component parts of the ore are lead and iron 
mineralized by the molybdic acid.* 
* The alkalies, whether caustic or combined with carbonic acid, do not act in the 
humid way on molybdsena when mineralized by sulphur. Scheele’3 Essays, p. 230; 
and Memoire sur la Molybdene, par M. Pelletier, Journ. de Physique, De- 
cembre, 1785, p. 437. 
MDCCXCVI. 
Qq 
