18 MEMOIRS NATIONAL ACADEMY OF SCIENCES. (vol.xiv. 



fore, taken up in connection with the present work and a detailed description of it has been 

 given in the Proceedings of the National Museum." The stone is there described as of a dark 

 greenish gray color, firm and compact, admitting of a polish and thickly studded with small, 

 dark, almost black chondrules and nodular masses of metal and troUite. A microscopic exam- 

 ination shows it to consist of a dense black irresolvable ground, throughout which are scattered 

 iron and iron sulphide, together with abundant sharp splinters of pyroxene and numerous more 

 or less fragmentary chondrules of the same mineral. No olivine, feldspar, or other sihcate min- 

 eral was determined. 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 abundant graphite. The sulphide of calcium, oldhamite, was detected both by chemical 

 means and by the microscope. The analyses yielded results as follows: 

 Metallic portion separated by mercuric chloride solution: 



X 6r cent. 



Iron(Fe) 90.44 



Nickel (Ni) 8.26 



Cobalt (Co) 18 



Phosphorus (P) 08 



Manganese (Mn) 1-04 



100.00 



Silicate portion, free as possible from the metal, sulphides, and graphite, yielded: 



Per cent. 



Silica (SiOj) 47. 970 



Alumina (AlA) 2.647 



Ferrous oxide (FeO) 19.283 



Phosphoric acid (PA) 699 



Manganous oxide (MnO) 175 



Nickel oxide (NiO) 739 



Cobalt oxide (CoO) 067 



Lime(CaO) 1.559 



Magnesia (MgO) 22.736 



Carbonic acid (CO,) 363 



Soda(Na20) Trace. 



Potash (K2O) None. 



Water (H2O) 3.762 



100.00 

 A recalculation of these analyses gives the following, showing the composition of the stone 

 as a whole: 



Per cent. 

 Silica (SiOj) 35.699 



Alumina (AlA) 1- 9C9 



Ferrous oxide (FeO) 2.5.790 



Manganoiis oxide (MnO) 130 



Nickel oxide (NiO) 549 



Cobalt oxide (CoO) 049 



Lime(CaO) 1.160 



Magnesia (MgO) 16. 920 



Carbonic acid (CO2) 271 



Phosphoric acid (PA) - 520 



Water (HA 2.799 



Iron(Fe) 10.400 



Nickel (Ni) 949 



Cobalt (Co) 020 



Phosphorus (P) 092 



Manganese (Mn) 119 



Carbon (graphite) (C) 310 



Sulphur (S) 5.100 



102. 846 

 Minus O for S 2. 54 



„ , . . . . , , , , , 100. 306 



No barium, strontmm, or zirconium could be detected. 



o Proc. U. S. Nat. Mus., vol. 49, 1915, p. 109. 



