30 



T. H. LABY. 



Insoluble 

 and Si0 2 

 weighed : 

 Si0 2 de- 

 termined 

 by H F 



and 

 HoSCL 



Diluted nitrate to 400 cc 3 

 solution. 



passed H 2 S through hot 



PbS, CuS, 

 Bi 3 S 3 , 



As 2 S 3 . 

 Lead 



weighed 

 asPbS0 4 ; 

 Bi pptd. 

 as BiOCl 



weighed 

 as Bi 2 3 ; 

 Cu colori- 

 metrically 

 as a trace. 



Filtrate concentrated to 200 cc. by boiling 

 30 cc. 3E Am 2 C0 3 + 10 cc. 15 E NH 4 H0 

 (excess must be avoided). H 2 S passed 

 through liquid when hot. 



FeS, MnS, 



A1 2 3 ?, 



ZnS\with 



some CaO 



but no rare 



earths; 



precipitate 



roasted 



and 



weighed, 



Fe was 



separated 



by basic 



acetate 



method; 



Mn by 



difference. 



Evaporated filtrate nearly to 

 dryness, dissolved the ppt. 

 (NH 4 ) 2 U 2 7 and U0 2 S in a 

 minimum of dilute HNO s . 

 Added fresh NH 4 HS digest for 

 some time. 



Uranium, rare earths 

 and calcium : dissol- 

 ved in HN0 3 evap- 

 orated to dryness ; 

 dissolved in water; 

 oxalic acid added. 



No rare 



Added 



earths 



NH 4 HO 



precipi- 



to precipi- 



tated. 



tate the 





calcium 





and 





uranium ; 





weighed 





as U 2 3 





+ CaO. 





Dissolved 





ppt. and 





deter- 





mined the 





CaO 





present. 



Magnes- 

 ium, trace 

 found. 



To the neutral solution in two separate analyses, no 

 indication of the presence of the rare earths was obtained. 

 Infthe light of Hillebrand's analyses of uraninites and of 

 Professor Strutt's work on the association of helium with 

 uranium there can be no doubt that this mineral contains 

 helium. I have no record of having determined the amount 



