284 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. XIII. 



BIBLIOGRAPHY. 



1. 1895: BREZINA. Wiener Sammlung, p. 307. 



2. 1895: WBINSCHENK. Meteoritenstudien I. 1. Long Island, Phillips County, Kansas. Tsch. Min. Petr. Mitth., 



Bd. 14, pp. 471-473. 



3. 1902: FARRINQTON. Meteorite studies I. Publ. Field Columbian Mus., Geol. ser., vol. 1, pp. 287-300. 



4. 1904: BBEZINA.. Catalogue of the Ward Coonley collection of meteorites, p. 98. 



Los Angeles. See Shingle Springs. 



LOS REYES. 



Mexico D. F., Mexico. 



Latitude 19 10 7 N., longitude 98 50' W. 



Iron. Medium octahedrite (Om). of Brezina. 



Found 1897; described 1902. 



Weight, 19.5 kgs. (43 Ibs.). 



This meteorite was described by Farrington, 1 who regarded it as probably a member of the 

 Toluca fall. Studies made in connection with this catalogue, however, make it seem probable 

 that it should be considered an independent fall. Farrington's account is as follows: 



This meteorite was obtained for the museum in the spring of 1897 from Mr. E. 0. Matthews of the City of Mexico. 

 It was brought him by some native Mexicans or peons who reported that they nad found it some months before at Los 

 Reyes while plowing. This is all the evidence obtainable regarding the manner of its discovery. The meteorite is 

 of the metallic variety (aerosiderite) and is a complete individual. Its weight entire is 43 pounds (19.5 kg.). Its 

 form (illustrated by cuts) is roughly that of a steep triangular pyramid whose greatest length is 24 cm. (9.5 inches), 

 and greatest width 15 cm. (6 inches). The sides of the pyramid are deeply hollowed and rounded so that the contours 

 of the mass are curved, and at one of the edges it extends out in the form of a thin wing. On, one side near the base 

 are two especially deep and well-marked pits side by side, one somewhat conical in shape, the other broadly concave, 

 The diameter of the conical pit is about 45 mm. (1.75 inehes) and its depth 20 mm. (0.75 inch). The concave pit is 

 about 63 mm. (2.5 inches) in diameter and 12 mm. (0.5 inch) deep. These pits probably mark areas of schreibersite 

 which were fused out during the passage of the meteorite to the earth. The surface of the meteorite is of a uniform 

 dark brown color from oxidation, but the depth to which oxidation has penetrated is very slight, as the merest scratch 

 with a file reveals the nickel-white color of the interior. The meteorite ia not of the "sweating" variety and exhibits 

 no tendency to further alteration. 



Its substance is tough and malleable to a high degree. It is medium hard, cutting with some difficulty with a 

 hack saw. It takes a good polish, a polished surface being of silver-white to nickel-white color. Relative to copper 

 sulphate the meteorite is active. 



The iron has not been sliced, but a triangular area 63 mm. by 25 mm. (2.5 inches by 1 inch) was made smooth and 

 etched with nitric acid. The surface etched easily and exhibited well-marked Widmanstatten figures. Two other 

 smaller surfaces were also etched on other portions of the meteorite. The figures of the meteorite show that it is to be 

 classed with Brezina's group 46 (octahedrite with lamellae of medium width) or Meunier's group 7 (arvaite). The 

 bands of the etching figures are not of uniform width nor do they extend continuously for any great distance. They 

 are of the type described by German writers as "wulstige" (swollen). The longest one is 11 mm. (0.45 inch) in length 

 and its contour is very irregular. Only the two alloys, kamacite and tsenite, seem to be present. The former is iron 

 gray in color and occasionally has a well-marked granular structure. The latter, filling the areas between the kamacite 

 bands, is now more or less ribbonlike and now occurs in curvilinear areas. Much of it appears connected through the 

 section, giving the impression of a network in which the kamacite is embedded. It shades to a bronze color as con- 

 trasted with the iron gray of the kamacite and is left standing in relief by the etching. Under the lens its surface 

 appears very rough, the etching of the acid acting upon it more irregularly than upon the kamacite. The only other 

 mineral appearing in abundance in the meteorite is schreibersite, which occurs in long narrow bands or in irregular 

 star like forms. These areas are bounded by kamacite (swathing kamacite). Decomposition has taken place usually 

 along the schreibersite bands, and these decomposed areas appear as dark marks on the etched surface. 



Troilite seems to be almost entirely absent from the meteorite. Only two minute nodules are to be seen on the 

 surfaces which have been etched and the percentage of sulphur obtained by analysis corresponds to a content of only 

 0.07 per cent. The presence of cohenite is indicated by the carbon found by analysis, but it was not observed on the 

 etched surfaces. 



An analysis of the meteorite was made by Mr. H. W. Nichols, the methods employed being briefly as follows: 

 Material for the analysis was secured by a boring made with a 0.25-inch drill. The amount of substance used was 

 2.4353 grams. In order to prevent loss of sulphur and phosphorus the borings were placed in a flask and first treated 

 with fuming nitric acid, to which they remained passive, and then hydrochloric acid was gradually added cold until 



