Genth.] 



The portion B gave : 

 1 



42 



Pb 

 Bi 



Cu 

 Te 



S 



2 

 39.34 

 6.28 

 21.43 



= 39.54 

 = 6.13 



= 23.00 



= lost — 18.53 — 



= 7.16 — — 



S required for 6.22 Pb to form PbS 

 S in tapalpite 



Ag : Bi : (TeS) = 0.365 : 0.102 



This ratio makes it probable that the portion B had a slight admixture 

 of telluride of silver. 



Deducting galenite, &c., the analysis would give the following per- 

 centage : 



Ag 

 Bi 

 Te 



S 



46.09 

 24.99 

 21.67 



7.25 



100.00 * 



Imperfect as these results may be on account of the noticed admixtures, 

 there can be very little doubt that tapalpite is a normal sulpho-telluro-salt 

 of silver and Jbismuth. Rammelsberg gives no lead in his analysis, and 

 may have had purer material at his disposal ; it is to be hoped that such 

 may be obtained for a subsequent investigation. 



VI. Allanite. 



A variety of allanite, closely resembling that from E^st Bradford, Ches- 

 ter county, Pa., and lilce the latter easily decomposed into a brown earthy 

 powder, has been sent to me by Mr. J. A. D. Stephenson, who discovered 

 it several years ago near Statesville, N. C. 



The pure has a brownish-black color and a pitchy lustre. Associated 

 with it are small zircons. 



Mr. Harry P. Keller has made the following analysis : 



18 990 / °^ which about 5 per cent CejOj, 

 the rest mostly Di^Oj, 



