Plate 22 



1. Iquique, Chile; nickel-rich ataxite; Xi-Co 16.35 percent. Typical structure of the 

 iron, a fine groundmass with occasional oriented needles or groups of short, rounded spindles 

 of kamacite. The iron etches slowly. Picra! 70 seconds; X 60. 



2. Iquique. Part of an area similar to figure 1 at high magnification. The taenite 

 borders of the spindles merge with the taenite of the groundmass. In places it is hard to 

 distinguish between particles of kamacite and of taenite, both sometimes appearing clear. 

 Where one component is darkened, however, it is always taenite, the kamacite invariably 

 being clear. Where the two are very minutely divided in some places a uniform black 

 results because of the strong attack of the etchant along their interfaces. Picral 70 seconds; 



X 600. 



3. Cape of Good Hope, Africa; nickel-rich ataxite; Xi-Co 16.62 percent. General 

 structure, a very fine gamma-alpha groundmass with occasional needles or spindles of kama- 

 cite. The black component is hydroxide. The iron etches very quickly, turning dark 

 and all structure disappearing. \'ery light picral; X 60. 



4. Cape, of Good Hope. Part of the area shown in figure 3, slightly stronger etching. 

 Dense, irregular paraeutectoid groundmass, with a minute kamacite needle in addition to 

 the large one. The latter surrounded by a clear taenite border. Additional etching for 

 10 minutes with neutral sodium picrate produced no effect, showing absence of phosphide. 

 Picral 15 seconds; X 300. 



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