Decomposition of lro)t Pyrites. 



371 



m inations of specific gravity on this mineral, which I have been 

 able to find. Those varieties were niekeliferous (from 3 to 11 

 per cent.), whose localities are given in italics. 



No 



Locality. 



s P . Qr. 



1 



Horbaeh, Baden, 



4.700 



2. 



EJefva, Sweeten, ... - 



4.674 



3. 



Freiberg, Saxony. 



4.642 



4. 



Elizabethtown, Ontario, Can., 



4.642 



5. 



Trumbull, Conn., 



4.640 



6. 



Locality unknown, 



4.631 



t. 



Uto, Sweden, - . . - - 



4.627 



8. 



Oonghonas do campo, Brazil, 



4.627 



9. 



Locality unknown, 



4.623 



10. 



Bodenmais, Bavaria, 



4.622 



11. 



Bodeumais. Bavaria, - 



4.622 



12. 



Elizabethtown, Ontario, Can., 



4.622 



13. 



Locality unknown, 



4.609 



14. 



Boden, Saxony, ... - 



4.605 



15. 



Oraigmuir, Scotland, - 



4.602 



16. 



Kongsberg, Norway, 



4.584 



17. 



Auerbach, Germany, - 



4.583 



18. 



Harzburg, Germany, 



4.580 



19. 



Hilsen, Norway, - 



4.577 



20. 



Xalastoc, Mexico, - 



4,564 



21. 



Bodenmais, Bavaria, - 



4.546 



22. 



Gap Mine, Pa., . . . 



4.543 



23'. 



Bodenmais, Bavaria, - 



4.540 



24. 



Cornwall, England, - - - 



4.518 



25. 



Mo6l Aelion, Wales, - 



4.518 



26. 



Treseburg, Harz Mts., - 



4.513 



27. 



Dobsehau, Hungary, - 



4.510 



28. 



In n vary, Scotland, 



4500 



29. 



Artificial, by ignition of pyrite, - 



4.494 



30. 



Piedmont, 



4.270 



31. 



Gap Mine, Pa., - 



4.190 



32. 



Rajputanah, India, 



2.580 



Analyst. 



C. Rammelsberg. 



J. Berzelius. 



Lindstrom. 



J. Lawrence Smith. 



C. Rammelsberg. 



Mohs. 



Lindstrom. 



O. F. Plattner. 



C. Rammelsberg. 



H. Rose. 



Schaffgotsch. 



Harrington. 



C. Rammelsberg. 

 Breithaupt. 



D. Forbes. 

 Lindstrom. 

 Petersen. 



C. Rammelsberii:. 



Sckaffgotsch. 

 C. Rammelsberg. 

 V. Leuchtenberg. 

 Hatchett. 

 Hatchett. 



C. Rammelsberg. 

 Breithaupt. 



D. Forbes. 



C. Rammelsberg. 



Tournaire. 



Boye. 



J. Middleton. 



Xot withstanding the repeated investigations which have been 

 devoted to this mineral by the great company of eminent chem- 

 ists, some of whose names are stated in this table, the question 

 of the true signification of the varying composition of this spe- 

 cies, it is acknowledged, remains still unsettled. As every fact 

 bearing on this subject may have some value, I will present be- 

 low some results of the comparison of the chemical composition 

 and density of the varieties of pyrrhotite. For this purpose, 

 we will accept the analyses as corrected by Habermehl, though 

 carrying them out to 100 per cent., when necessary. All the 



