20 



nFConns of the AUf^TRAT.iAX AirsErM. 



described in this paper lias smoother faoes and it was found possible to 

 measure its angles on a refleotinof j^onionietei-, but the measurements ai-e 

 by no means good. 



Mr. E. C. Andrews describes the mine as "a large gi'anular quartz 

 ' blow.' Worked by means of open cuts and shafts. Tm-egulai- masses 

 of pegmatite (large, dark, vitreous quartz, felspai' and black mica) bianch 

 repeatedly througli the ' quartz blow.' In these branches occur large 

 stout crystalline masses of fi'iable wolfram--'." The Torrington ore is 

 apparently near the ferberite end of the wolframite serie.s-"*, the re- 

 calculated analysis giving the percentage of manganous oxide as 3"95 

 (= Mn WOj 16-9%). 



The crystal measures 3 X 3 cm. along the directions of the h and c 

 axes, but it was evidently a much larger crystal befoie fracture. As in 

 wolframite the angle fi is fairly close to 90°, the value chosen by 

 Goldschmidt-'' being 89° 32', the mean of determinations by Descloiseaux, 

 Krenner and Seligmaun, it is not easy to detern)ine the positive or 

 negative character of the forms when the angular measurements, as in 

 this case, are not very accurate. The balance of the evidence favouis the 

 interpretation adopted, but, if the other setting is coriect, then o- (121) 

 and s- (121), ,j (111) and n (111) will be interchanged, and the foi-m 

 t (102), present as a narrow face terminating a small segment in parallel 

 position on d' will become // (102). 



The measured and calculated anales are tabulated below : — 



-' Andrews— Aim. Kept. Dopt. Mines, N.S.Wales, 1904(1905), p. 143. 

 -* Came— Dept. Mines, N.S.Wales, Min. Res. No. 15. 1911. p. 70 ; Hess— Bull. 

 U.S. Geol. Surv., 583, 1914, pp. .32-33. 



-3 Goldschmidt— Winkeltabellen. 1897. p. 300, 



