the Carinthian Molybdate of Lead. 293 
flame, it occasionally produced a glass, which was greenish 
' blue, and sometimes deep blue. 
3. With phosphate of ammoniac and soda it formed a sea- 
green glass, which in proportion to the quantity of the ore 
sometimes became deeper in colour so as to be nearly of a 
deep blue. 
Before I made the following experiments, I reduced eight 
ounces of the ore to a fine powder, and dissolved the matrix 
after the manner of Mr. Klaproth, by successively pouring 
on the powder small quantities of nitric acid diluted with six 
parts of distilled water, after which I edulcorated and dried 
the residuum. The nitric acid used in this operation con- 
tained (as Mr. Klaproth has mentioned) calcareous earth, 
oxyde of iron, and oxyde of lead ; but as prussiate of pot-ash 
produced a pale green precipitate, I suspected that some other 
metallic substance beside iron and lead was in the solution. 
I therefore added muriate of tin to a portion of it, which was 
immediately changed from a pale yellow to a pale blue, and 
shewed that a small quantity of inolybdic acid was present in 
the solution. 
§ III. Molybdate of Lead with Water. 
I boiled twelve ounces of distilled water on twenty grains 
of the purified ore in a glass matrass during three hours. The 
ore did not appear to be changed, nor did the water after it 
had passed the filter afford any trace of matter in solution. I 
believe, therefore, that the molybdate of lead is insoluble in 
water. 
