the Carinthian Molybdate of Lead. 307 
The muriate of lead, when edulcorated, I found to be per- 
fectly free from any other substance. 
I now saturated the acid solution (from which the muriate 
of lead had been separated ) with solution of carbonate of am- 
moniac, and obtained a pale yellow flocculent precipitate, 
which was well edulcorated. 
This precipitate immediately dissolved in very dilute nitric 
acid, and with sulphuric acid I precipitated a small portion of 
lead, after which,with prussiate of pot-ash, I separated a quan- 
tity of iron. 
The solution, when saturated with the ammoniac, was deep 
blue, and was composed of muriatic acid, ammoniac, and the 
blue oxyde of molybdaena, like that mentioned in the former 
experiment. 
In the course of these experiments, I have observed that the 
full blue colour only takeg place at the precise moment of sa- 
turation, and if the alkali is even added to a considerable excess, 
the colour does not suffer any farther change ; but if much 
water is first added, the blue colour does not appear ; or if 
water is added afterwards, the solution becomes colourless. 
By the preceding experiments the component parts of the 
ore are proved to be lead, iron, and molybdic acid. 
In respect to the small portion of siliceous earth, it may 
rather be regarded as accidentally present, than as an essential 
ingredient. 
My second object was to discover the least exceptionable 
mode of analysis, but all of those which have been described 
appeared to me to be liable to considerable objections, and I 
was therefore induced to make some additional experiments.. 
