METEORITES OF NORTH AMERICA. 125 



acid twice as concentrated as usual. The residue furnishes felted, tinder-like, aggregates that obviously consist of 

 pleasite which was composed of small complete lamellae in which the taenite bundles protected the kamacite nucleus 

 from action by the acid. 



Rammelsberg's 5 analysis showed Ni 5.12; Co 0.82. 

 Analysis by Cohen and Weinschenk gave: 



Fe Ni Co P residue 



90.23 8.76 1.21 trace trace =100.20 



Analysis of tsenite from the meteorite by Manteuffel 10 gave: 



Fe Ni Co 



65.39 33.20 L41 =100.00 



The specific magnetism was determined by Leick as 0.31 absolute units per gram. 

 Farrington JS has the following note in regard to the masses: 



The two known masses of this meteorite were found, as was stated at an early period, lying only about 800 feet apart. 

 This proximity and the jagged surface to be found on each renders it very probable, as was suggested by Daubree, if not 

 . earlier by others, that the two pieces once constituted a single mass which was torn apart during its fall to the earth. The 

 probable dimensions of this mass were given by Daubree as follows: Length 4.65 m. (16 feet), width 1.50 m. (5 feet) 

 and thickness 0.45 m. (22 inches). The dimensions thus obtained by Daubree were evidently arrived at by assuming 

 a joining of the two masses end to end. Such a joining, however, would not place the torn surfaces together. In order 

 to determine what the form and dimensions of the mass would have been if the two parts were joined along the fractured 

 surfaces, the two full-sized models of these masses in possession of the Museum were joined in this way. The resulting 

 form is shown in a plate. It is seen to be broad and tabular with irregular outline. Along the line where disruption 

 took place there was an evident constriction. The correspondence between the broken surfaces is such as to leave 

 little doubt that they were once joined. The dimensions of the mass so formed are: Length 12 feet (3.6 m.) and width 

 7 feet (2.1 m.). The weight of this mass would have totaled about 21 tons (20,881 kg.). It would be of interest to know 

 which surfaces of the two masses lay uppermost when found, but no record seems to have been made of this point. 

 There is a marked difference in the pittings on the two broad surfaces and they correspond on the two masses when 

 joined. Thus pittings on one side are deeper and narrower than those on the opposite side. The indications are 

 therefore that the side first mentioned was the front side in falling. 



As the writer is not aware that any photographs of the two original masses have ever been published, cuts from 

 photographs made by him in 1896 are presented. These show the masses as they are installed in the National School 

 of Mines in the City of Mexico. 



In addition to the data cited by Cohen it is stated in the Bosquejo Geologico de Mexico 1S 

 that the two masses lay at the foot of the eastern slope of the Sierra de Chupaderos at a distance 

 of 250 m. from each other in a north and south direction. 



The masses were removed in 1891 by the Mexican Government to the School of Mines of 

 the City of Mexico and are still there. The weights of the masses given at the heading of this 

 account are taken from the labels at the School of Mines. These weights differ slightly from 

 those given by Castillo 8 but are probably correct. 



BIBLIOGRAPHY. 



1. 1854: BARTLETT. Personal Narrative of Explor. in Texas, New Mexico, California, Sonora, and Chihuahua. New 



York, 1854, vol. 2, pp. 453 and 458. 



2. 1871: SMITH. The precise geographical position of the large masses of meteoric iron in North Mexico, with the 



description of a new mass. Amer. Jour. Sci., 3d ser., vol. 2, p. 337. 



3. 1871: BUHKART. Briefl. Mitt. Neues Jahrb., 1871, p. 851-852. 



4. 1876: BARCENA. On certain Mexican meteorites. Proc. Acad. Nat. Hist. Philadelphia, 1876, p. 122. 



5. 1879: RAMMELSBERG. Meteoriten, p. 32. 



6. 1880: Mrxoz LUMBIER: Los Aerolitos de Chihuahua. Mexico, 1880. 



7. 1889: FLETCHER. Mexican Meteorites, Mineral. Mag., vol. 9, pp. 99, 103, 104, 122-151, and 175. 



8. 1889: CASTILLO. Meteorites, pp. 6-8. 



9. 1891: COHEN und WEIXSCHENK: Meteoreisen-Studien I. Ann. K. K. Naturhist. Hofmus. "Wien, Bd. 6, pp. 131. 



132, 147-148 (analysis), 160, and 164. 



10. 1892: COHEN. Meteoreisen-Studien II. Ann. K. K. Naturhist. Hofmus. Wien, Bd. 7, pp. 150-151 (analysis), 



158 (Cu), 159, 160, and 161. 



11. 1893: MECXTER: Revision des fers me'teoriques, pp. 52 and 53. 



12. 1895: BREZINA. Wiener Sammlung, p. 269. 



13. 1897: Bosquejo Geologico de Mexico. Mems. 4, 5, and 6, p. 77. 



14. 1905: COHEN. Meteoritenkunde, Heft 3, pp. 346-350. 



15. 1907: FARRINGTOX. Meteorite Studies II. Publ. Field Columbian Mus., Geol. Ser., vol. 3, pp. 112-113. 



