METEORITES OF NOKTH AMERICA. 399 



and nickel (?). The original meteorite also contained traces of sulphur. The amount of insoluble matter varied in 

 different trials. 



From these analyses it is evident that this is one of the most remarkable meteoric irons yet examined, in the 

 large amount of nickel which it contains, being nearly 10 per cent. A very careful qualitative examination of the in- 

 soluble residue failed to detect appreciable quantities of those numerous various substances, i. e., cobalt, chromium, 

 copper, manganese, which are often found in meteoric irons, as was first shown by Berzelius, and confirmed by many 

 others. The peculiar form of carbon, however, which Berzelius first noticed, is found in small quantity in this speci- 

 men, and the remainder of the insoluble matter appears to have been a compound of silicon, nickel, and iron. 



Shepard 2 gave the specific gravity as 6.835. 



According to Reichenbach, 3 Salt River consists of a gray, amorphous, fine-grained ground- 

 mass which yields no figures upon etching (apparently plessite) with numerous intermingled 

 fine needles and points of lighter color (Glanzeisen) unaffected by acids, to which he traces, 

 here as in the case of the Cape iron, the high percentage of nickel. Cracks filled with graphite 

 are mentioned and an ingrowth of iron glass. 



Rose 4 distinguishes a gray, dull, groundmass and light elongated portions inclosed therein, 

 which are arranged somewhat regularly according to the sides of an almost equilateral triangle 

 and inclose longish, glistening shapes. According to the illumination after weak etching one- 

 half of the section appears lighter than the other. Disregarding the regular position of the 

 lighter portions, Salt River may according to him be compared with Senegal. 



In 1884, Meunier 5 described Salt River as a mixture of tsenite with iron carbide (camp- 

 belline), which yields very irregular figures by etching and established the fact of a carbon con- 

 tent. In 1893, 7 he explained that only braunine is present with schreibersite and rhabdite, 

 and remarked a high percentage of phosphorus as characteristic. Ho did not furnish a new 

 analysis, and neither his older nor newer characterization agreed with the results of Brewer's 

 analysis. 



In 1885, Brezina " placed Salt River in the same group of hexahedral irons which in the 

 arrangement of inclusions of schreibersite shows a uniform orientation throughout the entire 

 mass (Chesterville group). He remarked the surface of the meteorite covered with a rough 

 bark in places. 



Cohen 8 described the meteorite as follows: 



Salt River is distinguished by a very rich content of schreibersite, and in this respect is surpassed only by 

 Tocavita. This occurs sometimes in rounded grains 0.05 to 0.25 mm. in size, sometimes in elongated individuals, 

 which, however, are not bounded by such straight lines as is usually the case with typical rhabdite. The latter are 

 as a rule only 0.25 to 0.5 mm. long, but in exceptional cases attain a length of 4 mm. Where smaller individuals pre- 

 vail, they are massed in large numbers, closely compacted and quite evenly distributed; in the neighborhood of large 

 columnar crystals their number diminishes and the distribution is irregular. Such particles, poor in schreibersite, 

 viewed at some distance, come out quite distinctly as dark, dull spots upon the prevailing mass rich in schreibersite 

 and of a lighter, more lustrous appearance. 



The schreibersite is almost without exception completely surrounded with gray kamacite and tsenite lamellse, the 

 size of which stands in direct relation to the size of the grains. Then follow still other lamellae of similar constitution 

 without schreibersite inclusions; and since such lamellae are frequent I do not consider their occurrence accidental. 

 The lamellae free from inclusions have a breadth of some 0.02 to 0.15 mm. and consist of an extremely fine-grained 

 kamacite; the others, inclusive of the inclosed schreibersite, attain a breadth of 0.4 mm., and where these dimen- 

 sions are approximated — which is only very seldom the case — a considerably coarser kamacite occurs, which shows a 

 distinctly oriented luster in each individual grain. The light, brightly glistening tsenite borders are narrow, but under 

 the microscope are more sharply divided off from the kamacite. Between the lamellae lies a grayish-black, dull plessite, 

 in which appear under the glass tiny lustrous spangles. At about 200 diameters it shows a finely netted structure, 

 and it seems that the plessite is entirely made up of tiny lamellse of the same or very similar character with the 

 larger ones already described. In the portions poor in schreibersite the plessite forms a coherent background, in 

 which the lamellse lie isolated ; in the portions rich in schreibersite they occur in isolated constricted particles. 



Analysis by Dr. J. Fahrenhorst: 



Fe Ni Co Cu C S P 



90.89 8.70 0.85 0.04 0.02 trace 0.34 =100.84 



Mineralogical composition (estimated): 



Nickel iron 97. 80 



Schreibersite '. 2. 19 



Troilite 0. 01 



100. 00 

 Specific gravity (Leick), 7.6648 at 23.5° C. Nickel iron (estimated), 7.6786. 



