392 Ilillebrand — Occurrence of Nitrogen, in Uraninite. 



ing between them, for when Glastonbury uraninite was sub- 

 jected to the action of sulphuric or hydrochloric acids for dif- 

 ferent periods of time the residue was found to be enriched in 

 U0 2 and likewise in nitrogen, and this enrichment was more or 

 less according as much or little of the mineral had been dis- 

 solved. 



Whatever may be the eventual conclusion it will be found 

 that the small amount of water afforded by all analyses must 

 be carefully considered. Small as this quantity is, in conse- 

 quence of its low molecular weight as opposed to uranium, 

 thorium, and lead, it must play an important part in the min- 

 eral as a homogeneous whole or in one of its parts if a mixture. 

 In the latter case it will unquestionably be found to belong to 

 the more soluble component. 



Attention must be called to one difficulty presented by the 

 analyses for which no satisfactory explanation presents itself. 

 Analysis Y was made partly in duplicate with all possible re- 

 finements in order to ascertain whether or not the almost con- 

 stant plus in the summations of those preceding analyses in 

 which all constituents had been determined, or in which it was 

 evident that an excess would result by the estimation of the 

 one or two failing members, was due to impure reagents or to 

 faulty manipulation. The excess still appears, and it seems as 

 if some one of the weighings in all analyses must have been 

 uniformly too high. The cause cannot be sought in a replace- 

 ment of oxygen by nitrogen in combination with uranium as is 

 often allowable when fluorine is present in a mineral, for since 

 the nitrogen is freed as a gas by sulphuric acid it is immaterial 

 so far as the summation is concerned, whether the proportions 

 of U0 2 and TJ0 3 as found by titration are correct or not. A 

 certain amount of oxygen has been used, and it does not alter 

 the result whether this has been employed to oxidize a sub- 

 oxide of uranium to U0 3 , supposing nitrogen to have replaced 

 a part of the oxygen in TJ0 2 , or only in oxidizing U0 2 to U0 3 . 

 In the former case the actual percentage of U0 3 in the mineral 

 would be increased, but the oxygen consumed would be the 

 same. This matter will be further looked into. 



Other very mystifying points have been observed which 

 were revealed in a series of supplementary experiments on 

 Glastonbury uraninite which can here only be outlined in the 

 briefest manner. Experiment having shown that no nitrogen 

 could be obtained by H 2 S0 4 or by fusion with an alkaline 

 carbonate after sufficiently long ignition of the mineral in air, 

 it was sought to learn if the final change in weight by such 

 ignition represented the difference between loss of water plus 

 all nitrogen and gain of oxygen from oxidation of U0 2 . All 

 experiments made showed a considerable gain in weight, 



