24 CONTRIBUTIONS TO MINERALOGY. [bull. 262. 
is extracted from the residue by ammonia, as prescribed by Friedel 
and Cumenge, a little of the other constituents of the residue accom- 
pany the vanadium into solution. 
If the combination of the two methods is used, it is better, after the 
vanadium has been removed by distillation, to treat the two residues 
separately at first instead of to unite them at once. Full details of 
this treatment are unnecessary and would unduly extend this paper. 
Suffice it to say that from the uranium portion the little iron and 
aluminum present are separated b}^ ammonium sulphide and carbon- 
ate, and after removal of the latter and acidification the uranium can 
be thrown down by ammonium sulphide, and then by at least two 
precipitations by ammonia, or far better, by precipitating the neutral 
hydrochloric solution by freshly precipitated and alkali-free mercuric 
oxide at boiling- heat, as prescribed by Alibegoff/' As pointed out by 
von Foullon and also by Alibegoff, contrary to certain still widely dis-j 
seminated statements, ammonium sulphide does not afford a good sepa-i 
ration of uranium from calcium. This is perhaps especially true if the 
solution contains any phosphorus. Again, contrary to another state- 
ment, it seems perfectly possible to separate uranium completely* 
from alkalies by a few ammonia precipitations. 
The finally ignited and weighed U 3 8 was redissolved in nitric acid, 
filtered, if necessary (Si0 2 , A1 2 3 , Fe 2 3 ), and divided into two parts,] 
one of which was tested for the very little P 2 5 usually present, and) 
the other for vanadium by conversion into sulphate, reduction by sul- 
phur dioxide gas, and titration by very dilute permanganate solution. 
ANALYSES OF CARNOTITE ORES. 
I. Copper Prince claim, Roc Creek, Montrose County, Colo. 
According to the donor of the specimen, Mr. J. R. Duling, l-a is 
from the same lot as that from which Mr. Poulot obtained the speci-j 
mens afterwards analyzed by Friedel and Cumenge. 
II. Yellow Boy claim, La Sal Creek, Montrose County, Colo. 
III. Yellow Bird claim, La Sal Creek, Montrose County, Colo. 
The last two claims belong to the same group and the ore is from 
the same "blanket" (Voilleque). 
\-b and II-&, the first analyses made, are not strictly comparable 
with the other analyses, since they represent the effect of warm dilute 
hydrochloric acid, whose greater action is shown by the nearly com- 
plete solution of the ferruginous admixture. Cold, dilute nitric acidl 
was used for the other analyses. 
a Ann. Chein. u. Phar., vol. 233, 1886, p. 133; Zeit fur anal. Cliemie, vol. 26, 1887, p. 632. 
