Mr. Hatchett's Analysis of 
sg6 
§ V. Molybdate of Lead with Sulphur. 
A mixture, composed of fifty grains of the ore and 150 
grains of sulphur, was put into a small glass retort, to which 
a receiver was luted. 
The fire was then gradually raised till all of the sulphur was 
driven over, and the bottom of the retort began to melt. 
The residuum was a black loose powder, which was greasy 
to the touch, and soiled the fingers like molybdasna. 
This black powder was digested in a strong heat with nitric 
acid, diluted with three parts of water. 
Nitrous fumes were discharged during the digestion,' and 
the powder was dissolved, excepting a residuum of molybdic 
acid, which was of a greenish-yellow colour. 
The solution was diluted with an equal quantity of distilled 
water, and was filtrated. Sulphuric acid was then added till 
all of the lead was precipitated ; after which I obtained a brown 
precipitate by prussiate of pot-ash.* 
§ VI. Molybdate of Lead with Carbonate of Ammoniac. 
A mixture, composed of 50 grains of the ore and 220 of dry 
carbonate of ammoniac, was put into a glass retort, and was 
sublimed with a gentle heat. 
The molybdate of lead remained in the retort without hav- 
ing suffered any apparent alteration. 
The ammoniac, however, had raised a small portion ; for 
* As the quantity of molybdic acid in the, ore is much greater than that of iron, it 
is scarcely possible to discover the latter when they are precipitated together by prus- 
siate of pot-ash. 
