110 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.49. 



analysis. The presence of carbonic acid, as shown by the analysis, 

 suggested the mineral breunnerite, but this could not be determined 

 absolutely owing to the obscuring effect of the graphite already men- 

 tioned, although the solution obtained by boihng for a few minutes 

 in dilute (1-4) hydrochloric acid reacted distinctly for magnesia. 

 The calcium sulphide, oldhamite, was, however, detected first by 

 chemical means and afterward by the microscope. The mineral 

 occurs in the slide in the form of irregular areas, sometimes inter- 

 stitial and sometimes inclosed in the enstatite. It is of a yellow 

 brown color, sometimes greenish, completely isotropic, and with well 

 developed cubic cleavage. Attempts at isolation of the mineral 

 failed. Microchemical tests were also rendered futile by the abun- 

 dant hydrogen disulphide given off when the slide was treated with 

 even the most dilute acid. On boiling 9.35 grams of the fmely pul- 

 verized stone for one hour in distilled water the solution, smelling 

 distinctly of HoS, yielded 0.464 per cent CaO, the equivalent of 0.596 

 per cent CaS. 



Analyses of the stone by Dr. J. E. Wliitfield yielded the results 

 given below: 



Metallic portion separated by mercuric chloride solution. 



Per cent. 



Iron(Fe) 90.44 



Nickel (Ni) 8. 26 



Cobalt (Co) 0. 18 



Phosphorus (P) 0.08 



Manganese (Mn) 1-04 



100. 00 



Silicate portion, free as possible from the metal, sulphides, and 

 graphite, yielded: 



Per cent. 



Silica (SiO^) 47. 970 



Alumina ( AI2O3) 2. 647 



Ferrous oxide (FeO) 19. 283 



Phosphoric acid (P2O5 0. G99 



Manganous oxide (MnO) 0. 175 



Nickel oxide (NiO) 0.739 



Cobalt oxide (CoO) 0. 067 



Lime (CaO) 1.559 



Magnesia (MgO) 22. 736 



Carbonic acid (CO,) 0. 363 



Soda (NaoO) Trace. 



Potash (K2O) None. 



Water (H2O) 3. 762 



100. 00 



Independent determinations showed 13.296 per cent of FeS and 

 0.31 per cent of graphite. 



