Temperature of Sublimation. 9 



RTe 2 ; RTe 3 ; Te. t o m 



8. Calaverite. (AuAg)Te 2 . Kalgoorlie TeO 450 ; TeO a 675 



9. „ ., Cripple Creek ... ,, 520; „ higher 



10. „ „ „ 530; „ 600 



11. "Pefeite "'(?). PbTe 3 . Red Cloud Mine. „ 460; „ 900 



12. Tetradymite. Bi 2 Te 3 . Hungary „ 460; „ 750 



13. „ ~, Schonbkaw, „ 480; „ 750 



Schemnitz. 



14. Nagyagite. Au 2 Pb u Sb 3 Te T S 17 . Nagyag , 440; „ 610 



15. „ „ „ „ 525; „ 610 



16. Sylvanite. AuAgTe 4 . „ 460; „ 770 



17. „ „ Loo.? „ 480: „ 780 



18. „ „ Kalgoorlie „ 520; „ 730 



19. Coloradoite. HgTe. „ „ 520; „ 835 



20. Native Tellurium. Facebay, Tran- „ 525 ; „ 850 



sylvania. 



21. Tellurium, prepared. „ 525; „ 850 



22. ., "pure." „ 470; „ 700 



Two substances in this Table require special notice. 

 No. 10 was obtained by purchase and reached me labelled 

 " Petzite/' On obtaining the result recorded in the table, 

 it was concluded that the identification must be in error. 

 Petzite is a monotelluride o£ gold and silver. As such it 

 should first yield the white sublimate of Te0 2 . A rough 

 quantitative analysis on the apophorometer was made. A very 

 high percentage of tellurium was arrived at — nearly 80 per 

 cent, Some oxide of" lead was, how T ever, included, an ex- 

 cessive temperature having been employed. Mr. J. R. 

 Cotter was so good as to make for me a quantitive analysis 

 in the ordinary w T ay. The result was : — 



Tellurium 57*54 



Lead 33-70 



Iron 1-22 



Insol. inHN0 8 ••• ^' 77 



The insoluble part was found to contain an amount of 

 gold equal to 0'47 per cent, of the mineral. The balance 

 was insoluble in aqua regia, and was determined as mainly 

 silica : evidently an impurity. Silica is visibly associated 

 with the mineral. 



An earlier analysis gave Mr. Cotter a slightly larger 

 percentage of tellurium. 



The density taken on a clean homogeneous fragment was 

 found to be G*55. 



