[JOHNSTON-ELLSWORTH] ANNAHELM METEORITE 89 



number of polyhedral grains with well-defined boundaries, resembling 

 the structure of a iron or ferrite (PI. Mil, Fig. 8; PI. XI, Fig. 13). 



The areas enclosed by phosphide and high nickel alloy may 

 represent crystals which were stable only under conditions of high 

 temperature and pressure and which, on cooling, were transformed to 

 ordinary ferrite. 



The experiment involving fractional solution of the ground mass 

 (Analysis 5, page ) indicates that it consists of an alloy of 93 . 10% 

 iron with 6.90% of nickel, cobalt and copper. In its present con- 

 dition it may be considered as nickel-cobalt ferrite. 



Embedded in the ground mass are very numerous long slender 



crystals of phosphide (FeNiCoCu)3P (PI. XI, Figs. 13, 14; PL XII, 



Figs. 15, 16; PI. XIII, Fig. 17). These crystals usually have a 



definite arrangement with long axes either parallel to or normal to 



the lamellae of 38% nickel alloy. When cut more or less normal to 



their long axes they appear sometimes square (PI. XII, Fig. 15), 



sometimes rhombic in section (PI. XII, Figs. 15, 16; PI. XIII, Fig. 17). 



d produce a rhombic 



il may give a square 

 ERRATA SECTION IV. • , , , 



vations whether the 



Page 89 line K), for PI. XII., Fig. Ifi, read PI. XIII., the residue from the 



)ers of these crystals, 

 Page 89, line 17, delete PI. XIII., Fig. 17. ^^^^^^^ ^^^ ^^^^ ^^^ 



Page 91, PI. VI., line 4, for Figs. 7 and 8, read PI. IX., ssfully mounted and 



Figs. 9 and 10. .... ^ . 



aps, a millimetre in 



differ somewhat in 



colour and lustre. One, giving good reflections, was perfectly square 



in section with angles of 90° and hence was probably tetragonal. The 



other appeared to be rhombic though, owing to the vicinal character 



of the faces, there might be a difference of 10° in readings by different 



observers. This crystal was measured independently by E. Poitevin 



and myself, the measurements indicating the presence of the front 



and side pinacoids and a prism m near arsenopyrite. 



The artificial phosphides of iron have been studied in great 



detail by J. E. Stead. i According to him, in melts of iron containing 



over 10.2% P, which is the composition of the eutectic, crystals of 



FesP are produced. In the microphotograph (Loc. cit. Plate IV, 



No. 5) the crystals of FcgP appear mostly rhombic in section, but 



in the upper right hand quadrant may be seen one which is square in 



outline. Stead considered that the crystals were rhombic, but it is 



'Journal of the Iron and Steel Institute, Vol. LVIII, No. 11, 1900. 



