COMPOSITION OF FKKUKKl TE AND OTllEIi MEMUEUS OF SERIES. 31 

 thf irolfrtunite series Continued. 



excess of 0.2 and to this has been added 2.6, the equivalent of the Fe 2 3 given. In 

 appearance the material is so pure that it is difficult to account for the apparent 

 presence of 3.3 per cent of scheelite (CaWO 4 ). Possibly the "H 2 O above 110 C., 

 0.57," should be C0 2 . 



62. Wolframite from Cash tin mine, Irish Creek, Rockbridge County, Va. Analysis 

 by J. G. Dinwiddie. The analysis also shows Fe 2 O 3 , 4.03; FeO, 11.56; H 2 O 

 at 110, 0.12; H 2 O above 110, 0.63; TiO 2 , 0.02; A1 2 O 3 , 0.32; CO 2 , 0.5. The 

 Fe 2 O 3 has been changed to FeO and added to that item. It is extremely difficult to 

 make accurate determinations of ferric and ferrous iron in the wolframites, owing to 

 the likelihood of part of the iron being oxidized during grinding and difficulties 

 inherent in the chemical determination. The change also makes the analysis foot 

 up better. The scheelite (CaWO 4 ) is very high, (21.1), but specimens of wolframite 

 from the locality show many inclusions of scheelite. (See PI. XIV.) 



63. Wolframite from Neuhaus Stollberg, Stassberg, Harz Mountains, Germany. 

 Analysis by Petzold. Schneider, R., Ueber einen harzer Wolfram: Poggendorf's 

 Annalen, 4th ser., vol. 3, p. 474, 1854. 



64. Wolframite from the Germania mine, Cedar Canyon, Stevens County, Wash. 

 R. C. Wells, of the U. S. Geol. Survey, analyst. 



65. Wolframite from Chanteloube, Limoges, France. Kerndt, T., Ueber die Krys- 

 tallform und chemische Zusammensetzung der naturlichen und kunstlichen Verbind- 

 ungendes Wolf rammetalles : Jour, prakt. Chemie, vol. 42, p. 105, 1847. 



66. Wolframite from Harzgerode, Germany. Kerndt, T., Ueber die Krystallform 

 und chemische Zusammensetzung der naturlichen und kunstlichen Verbindungen 

 des Wolframmetalles: Jour, prakt. Chemie, vol. 42, p. 105, 1847. 



67. Wolframite from "Monte Video," country not given, Kerndt, T., Ueber die 

 Krystallform und chemische Zusammensetzung der naturlichen und kunstlichen 

 Verbindungen des Wolframmetalles: Jour, prakt. Chemie, vol. 42, p. 102, 1847. 



