Seybert’s Analysis of Chromat of Iron. 321 
. The residue on the filter (2,) supposed to be molyb- 
die acid and sulphur, was washed and dried ata moderate 
ammonia, and was therefore considered pure. e results 
in (B and C.) give a total of molybdic acid, amounting to 
4.465 grammes, equivalent to 2.971 grammes of molydenum 
on five grammes, or pr 100== 59.42. 
The constituents of the mineral according to this analysis, 
are, : 
Per 100 parts, 
A. Sulphur, - - 39.68 
€, Molybdenum, - - 59.42 
99.10 
100.00, 
000 90 Loss. 
Arr. XIII. — Analysis of the American Chromat of Iron; by 
Henry Seysert, of Philadelphia. 
Tuts mineral was found at the Bare Hills, near Baltimore, - 
in the State of Maryland ; the specimen submitted to anal- 
ysis was amorphous, and incrusted with talc. Its colour 
was blackish-brown—colour of the powder deep reddish 
rown. Lustre metallic—opaque—tfracture uneven—not 
very frangible—scratches glass—acts but very slightly on 
the magnet. The specific gravity , of a pure piece, was 
4.0639. Infusible before the blowpipe. 
Analysis. 
A. 8 grammes of the mineral, after being carefully sepa- 
rated from the talc, were reduced to a very fine powder, 
and exposed to a red heat in a platina crucible. The cal- 
cmed mineral was a shade darker. and weighed 7.87 gram- 
3 
