T. L. Walker— Tung stite and Meymacite. 307 



On analysis of that portion soluble in ammonia it was found 

 to yield 80 - 08 per cent W0 3 , the balance not accounted for by 

 the insoluble dried at 110° C. being apparently water. This 

 amount agrees very closely with the difference between the 

 percentage of water contained in the powder sample as a whole 

 and that contained by the insoluble portion. As scheelite, 

 wolframite and limonite appear to make up the insoluble part 

 of the sample, we va^y indicate the approximate mineralogical 

 composition of our aggregate as follows : 







WOa.H.O 



FeO.W0 3 



CaO.W0 3 2Fe 2 3 .3H 2 ( 



wo s .___ 



86-20^ 



80-08 



3-88 



2*24 





CaO .... 



•54 



.... 







•54 







FeO .... 



1-21 







1-21 





... 



Fe 2 G 3 ... 



4-14 













4-14 



H 2 0._._ 



7-72 



6-21 







-- 



•69 





86'29# 



5-09^ 



2-78^ 



5-83$ 







rtmgstite 



Wolframite 



Scheelite 



Limonite 



•82 



The material soluble in alkali is therefore hyd rated tungstic 

 acid, W0 3 .H 2 0. Since the mineral of Silliman has never been 

 analyzed and that of Carnot was so impure that nearly half of the 

 constituents found had to be rejected in calculating his formula 

 W0 3 .2H„0, it seems very probable that all three of these 

 occurrences have really the same chemical composition. 



This mineral is probably widely distributed as indicated by 

 the following extract from the " Economic Resources of the 

 Northern Black Hills."* The reference is to the formation of 

 secondary products by the alteration of wolframite. 



" Despite the decomposed and gouge-like character of the 

 country rock, alteration has not generally taken place to any 

 noticeable degree. Where the ore has been long exposed to 

 atmospheric conditions, however, a mineral of gold-yellow 

 color, in glistening druses of extremely minute crystals, very 

 often coats the surface. This has been considered by Forsyth 

 as suggestive of tungstite or tungsten trioxide, but none of 

 that collected by the writer gave satisfactory results to tests 

 for tungsten and its true character has not yet been deter- 

 mined." 



Some of the gold quartz mines in Southern British Colum- 

 bia in the vicinity of Salmo have, according to report, pro- 

 duced considerable amounts of this mineral, but as nobody 

 suspected the presence of any valuable substance other than 

 the gold, it does not appear to have been utilized. 



* Irving, Emmons and Jagger, U. S. Geol. Survey. Professional Papers 

 No. 26, p. 166. 



