uiT. 21 OXIDATION OF METEOEIC lEOKS SHANNON 11 



It will be seen from the last total that there is not sufficient ferric 

 iron to form limonite with all of the water if the formula 

 SFesOsSHgO is assumed for the latter. Limonite is variable in water 

 content, however, it being the amorphous equivalent of goethite with 

 the formula FeoOgHgO/nHoO. The difference in the water content 

 of this and Whitfield's results suggest that he dried his sample at or 

 near 100° before analysis. It is obvious that enough water is present 

 in the last sample to form limonite with all of the ferric oxide so 

 that the magnetic susceptibility of this portion at least must be 

 credited to the 19.14 per cent of trevorite and magnetite shown by 

 the last tabulation. 



The powder obtained by grinding the Coldwater material to pass 

 an 80 mesh sieve was between cinnamon brown (XV-15'-Z3) and 

 Front's brown (XV-15'-???) Ridgway in color. By working over it 

 with a hand magnet it was found to be attracted 88.3 per cent, un- 

 attr acted 11.7 per cent. The attracted and unattr acted portions were 

 identical in color and appearance. 



OXIDIZED OUTER ORUST OR SCALE FROM THE YORK METEORITE 



For comparison with the foregoing a sample of the scale from the 

 York, Greenland, meteoric iron consisting of flat brown flakes was 

 examined. The flakes were up to 3 centimeters broad by 1 to 3 

 millimeters thick and, although consisting principally of oxides, they 

 showed metallic particles upon grinding. The metal was removed in 

 large part by screening out the flattened particles from the agate mor- 

 tar, and only a small part of the metal passed through an 80-mesh 

 sieve. The powder which passed 80 mesh was separated into magnetic 

 and nonmagnetic portions with a horseshoe magnet. Both these 

 powders were about Mars brown (13''??^-) Ridgway, in color. The 

 proportions of the rough separation were as follows : 



Per cent 

 Metal 11. 4 



Magnetic 85. 



Nonmagnetic 3. 6 



100.0 



Only the magnetic oxide was further examined, and this, partially 

 analyzed by the method of procedure above, gave the following 

 results : 



Per cent 



Insoluble 1. 86 



FeaOs 65. 97 



FeO , 9. 52 



NiO 6. 78 



H2O 12. 44 



96.57 



