Vanadiferous Minerals in Western Colorado. 139 



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 cannot have been weighed with 

 the known constituents. The researches of M. and Mine. 

 Curie have shown that these ores contain traces of radio-active 

 elements, precipitated the one by hydrogen sulphide, the other 

 by sulphuric acid. Their presence, however, in quantity suffi- 

 cient 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 uncer- 

 tain 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 to obscure any simple rela- 

 tions that might exist.* 



Another difficulty is the impossibility of knowing what con- 

 stituents 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 by 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. The alumina 

 doubtless is derived from the vanadiferous silicate which seems 

 to exist in all the ores and which is not quite insoluble in cold 

 dilute acids. If so, a small portion of the vanadium, potassium, 

 magnesium, and water are to be attributed to this mineral, but 

 a general correction based on the analysis of this compound 

 (see p. 143) would not be justifiable. Its application leads to 

 nothing definite, even in the case of the particular ore 'No. Ill, 

 from which the silicate analyzed was derived. 



In the following tables are given first the recalculated analy- 

 ses and then the molecular ratios. All those constituents have 

 been excluded which pretty certainly do not belong to the 

 carnotite, but small portions of some of those retained are 

 unquestionably extraneous. In two cases (I-a and I-o) a certain 

 proportion of lime has been arbitrarily excluded equivalent to 



* According to Dr. Harry C. Jones of Johns Hopkins University, who very 

 kindly undertook to examine a specimen of the Copper Prince ore for rare gaseous 

 elements, helium is not present. Faint hydrogen lines were observed, the source 

 of which was ascribed to water vapor. Other lines, due probably to hydrocarbons, 

 were fairly strong, but the specimen had been long enough exposed in our 

 laboratory and elsewhere to have accumulated enough dust to account for them. 



Am. Jour. Sci.— Fourth Series, Vol. X, No. 56.— August, 1900. 

 10 



