26 CONTRIBUTIONS TO MINERALOGY. [bill. 262. 
DISCUSSION OF THE CARNOTITE ANALYSES. 
It will be noted that a somewhat marked deficiency appears in most 
of the analyses, the cause of which is quite unknown. Great care was 
exercised in most cases and especially in those which show the greatest 
loss. It seems hardly possible that any serious constant loss of a 
known constituent should have occurred, but the only alternative 
demands the presence of an element or elements unnoticed and which 
can not have been weighed with the known constituents. The 
researches of M. and Mme. Curie have shown that these ores contain 
traces of radio-active elements, precipitated the one b}^ hydrogen 
sulphide, the other by sulphuric acid. Their presence, however, in 
quantity sufficient to account for the observed losses in the above 
analyses, especially when 10 grams of ore were operated on, could not 
possibly have escaped observation. To whatever cause it may be due," 
this loss alone suffices to render somewhat uncertain any calculations 
based on the analytical figures, though if the loss is to be ascribed to 
uranium or vanadium the ratios would not be sufficiently affected tq 
obscure any simple relations that might exist. a 
Another difficulty is the impossibility of knowing what constituents 
to exclude and what to include in deducing molecular ratios. It is 
certain that most if not all of the iron is foreign to the yellow body. 
It is probable that phosphorus is likewise so, since its extraction bfl 
dilute acids does not keep pace with that of the uranium and vanadium. 
It may possibly be in. combination with the iron, in part at least. Thek 
alumina doubtless is derived from the vanadiferous silicate which 
seems to exist in all the ores and which is not quite insoluble in coldi 
dilute acids. If so, a small portion of the vanadium, potassium, mag- 
nesium, and water are to be attributed to this mineral, but a general I 
correction based on the analysis of this compound (see p. 30) would 
not be justifiable. Its application leads to nothing definite, even ir 
the case of the particular ore No. Ill, from which the silicate analyzed j 
was derived. 
In the following tables are given first the recalculated analyses anc j 
then the molecular ratios. All those constituents have been excludeoj 
which pretty certainly do not belong to the carnotite, but small portion. 1 
of some of those retained are unquestionably extraneous. In two case, 1 J 
(1-a and I-b) a certain proportion of lime has been arbitrarily exclude( j 
equivalent to the acid anhydrides C0 2 , Mo0 3 , and S0 3 , less what it 
needed to offset PbO and CuO. 
"According to Dr. Harry C. Jones, of Johns Hopkins University, who very kindly undertook! II 
examine a specimen of the Copper Prince ore for rare gaseous elements, helium is not presen 
Faint hydrogen lines were observed, the source of which was ascribed to water vapor. Other line: 
due probably to hydrocarbons, were fairly strong, but the specimen had been long enough expose 
in our laboratory and elsewhere to have accumulated enough dust to account for them. 
