Meteorite Collection — Handbook and Catalogue. 19 



The association of iron and nickel in the form of an alloy was 

 long thought to be a peculiarity of meteoric bodies, but at least two 

 terrestrial minerals are now known, which are constituted of such an 

 alloy. One of these, awaruite (361), contains 67% of nickel to 31% 

 of iron, the other, josephinite (367), 60% of nickel to 23% of iron. 



The iron found in large masses on Disco Island and other parts 

 of West Greenland also resembles the aerosiderites very closely in 

 composition, since it contains from 1 to 6% of nickel and small per- 

 centages of phosphorus and carbon. 



These occurrences are so isolated, however, that in general, masses 

 of iron alloyed with nickel, when found upon the earth's surface, may 

 be regarded as being probably of meteoric origin, especially if they 

 also exhibit a crust and pitted surface like that described, and etch- 

 ing figures such as will be mentioned later. 



Other elements commonly occurring in the aerosiderites, though 

 in much smaller quantities, are copper, cobalt, manganese, phosphorus, 

 sulphur and carbon. 



The phosphorus is usually combined with iron in the form of 

 schreibersite, the sulphur with iron as troilite, while the carbon may 

 be either free in a graphitic form or as minute diamonds, or com- 

 bined with iron. 



The proportions of the different elements as they commonly oc- 

 cur in the aerosiderites are illustrated by the following analyses of 

 some of those represented in the collection: — 



Fe. Ni. Co. Cu. P. 



(1) Toluca (7) 90.72 8.49 0.44 .... 0.18 X .03 =100.46 



(2) Braunau (55) 91.88 5.52 53 2.07 .... C, S tr. =100. 



(3) BatesCo.Mo (95) 89.12 10 02 0.26 0.01 0.12 =99.53 



(4) Grand Rapids, Mich. (116) 88 71 10 69 .... 07 20 COO S 03 =99.82' 



(5) Glorieta Mt, N. M. (122) 87.93 11.15 0.33 .... 0.36 =99.77 



(6) St. Croix Co., Wis.. (125) 89.78 7.65 1.33 tr. 0.51 C tr. Sn/r. = 99.27 



The specific gravity of the meteoric irons ranges between 5.75 

 and 8.31, nearly all lying between 7.5 and 7.9. 



Most meteoric irons present a distinct crystalline structure, the 

 features of which are brought out by etching a polished surface with 

 acids. There then appear upon the surface, bands or lines intersect- 

 ing one another at various angles, according to the direction of the 

 section. These are enclosed in a more or less unindividualized 

 ground mass. 



(1) Taylor, Am. J.Sc. Vol. 22 p. 374, 1856; (2) Duflos and Fischer, Pogg. Ann. Vol. 72, pp. 170, 475, 18- 

 47; (3) J- L. Smith, Am. J. Sc. 3rd series, Vol. 13, p. 213, 1877; (4) Riggs, ibid, Vol. 30, p. M2, 1885; (5) 

 Mackintosh, ibid, Vol. 30, p. 238, i88j; (6) D. Fisher, ibid, Vol. 34, p. 381, 1887. For further analyses 

 see Lithological Studies by M. E. Wadsworth, Mem. Mus. Comp. Zool., Harvard Coll., Vol. XI, Part 

 I, Oct. 1884. 



