METEORITES OF NORTH AMERICA. 117 



Burkart 2 practically repeats these observations as follows: 



In Charcas, the large iron meteorite from the hacienda del Sitio ia placed near the church as a curbstone. The 

 projecting piece has a height of 2 feet 8 inches. The whole mass may have a volume of 1.7 cubic feet and weigh 800 

 to 900 pounds. The surface, showing many rounded hollows, has by rain and wind lost its natural color. 



Daubr6e 4 described the meteorite as follows: 



The academy will doubtless be interested to know that the Mexican meteorite which four months ago Marshal 

 Vaillant announced had been sent to France has arrived at the geological gallery of the museum. Mexico is one of 

 the regions of the globe in which many masses of meteoric iron are known. Burkart, Councillor of Mines of Prussia, 

 who resided a long time in the country, enumerates in a recent interesting memoir nine distinct localities. 



On leaving for Mexico, I gave Marshal Bazaine a copy of this work and expressed the wish that one of these masses 

 might be obtained for France. Honoring this request with a kindness of which the friends of science should show 

 warm recognition, the commander in chief of the expedition corps obtained at Charcas, in the State of San Luis Potosi, 

 the mass of meteoric iron which has lain there from time immemorial. In spite of the enormous difficulty of moving 

 a mass of such weight it was sent to France and offered to the emperor, who kindly placed it in the museum. This 

 beautiful mass of meteoric iron forms now in our geological gallery a worthy companion to that of Caille. 



Mentioned in 1804 by Sonneschmid and seen in 1801 by Humboldt, this mass of meteoric iron lay at the northeast 

 corner of the church of Charcas, partly buried in the soil. Charcas is a little village situated about 23 iy north lati- 

 tude in the State of San Luis Potosi. It is 75 km. south of Catorce, and 172 km. northeast of Zacatecas, where equally 

 large masses of meteoric iron have been found. It is said that the meteorite of Charcas was moved from the hacienda 

 of San Jos del Sitio, 50 km. distant. The weight of the meteoric iron of Charcas is 780 kg. It is about 1 m. high, 

 47 cm. long and 37 cm. thick. The iron presents everywhere its natural surface. Its general form is that of a trun- 

 cated triangular pyramid with smoothed edges. One of the most remarkable features is the nearly flat face which 

 extends entirely across the mass. This represents what is called in Germany the front side in opposition to the rear 

 side. One of the corners of the pyramid is replaced by a large depression 30 to 36 cm. in diameter. This is bordered 

 by a wall nearly perpendicular to the bottom, which is 10 cm. deep. There is also a series of small depressions nearly 

 circular in form, shallow, and resembling small cups like those seen in the meteoric stones. They are not exclusively 

 confined to the large cup, but may be seen, though in less numbers, in other portions of the surface. Elsewhere, 

 depressions occur reminding one of marks left by raindrops upon a soft surface, also cylindrical cavities like those in 

 the iron of Caille. These are evidently due to dissolved troilite nodules. Their length varies from 5 to 10 mm. and 

 their depth attains 20 mm. Like those of Caille, they are parallel and appear to have a general orientation in accord- 

 ance with the crystallization. From one face of the meteorite portions have been detached, showing that the iron is 

 of remarkable whiteness. It takes a polish easily and becomes brilliant. Thtese polished surfaces show also frequent 

 troilite nodules like those on the surface. Widmanstatten figures appear very neatly on the polished surfaces with 

 acid, but they have not the regularity of those of the iron of Caille. Schreibersite appears in little isolated grains. 

 These appear in part oriented parallel to the faces of an octahedron and in part to the faces of a dodecahedron, as is 

 shown upon a specimen which I have cut in the form of a sphere. The action of acid makes significant planes which 

 may be perceived on portions of the oxidized surface. These pass through the curvatures of the iron showing that 

 they are not subsequent to the crystallization of the mass. The density of the iron is 7.71. After fusion it does not 

 present the characteristic figures of natural iron. It dissolves in acid rather slowly. The solution is accompanied 

 with the disengagement of hydrogen sulphide, showing decomposition of the iron sulphides. A residue of 0.2 per cent 

 is left and the solution contains principally iron and nickel. Meunier found, in a piece containing no visible troilite, 

 iron 93.01, nickel 4.32, traces of sulphide and silica, and 0.7 per cent of insoluble residue. Besides a small quantity 

 of white amorphous substance which appears to be silica, the insoluble residue consists of bright metallic and very 

 magnetic needles of schreibersite. It contains also a black, earthy, amorphous matter which does not give reactions 

 for sulphur or chromium, and is probably graphite. This constitutes 71.42 per cent of the residue, the phosphide 

 being 28.58 per cent. The iron sulphide forming the cylindrical nodules above mentioned is of metallic luster and 

 bronze-yellow color. A powder examined under the microscope shows indications of crystalline form. Treated with 

 boiling hydrochloric acid the sulphide is dissolved with evolution of hydrogen sulphide. In the solution a large 

 quantity of iron is present but no trace of nickel, but the solution is not complete; a black amorphous residue remains. 

 This contains no sulphur. There occur also small grains of an uncolored, transparent substance like those observed 

 in Caille. Examined under the microscope one sees fragmentary forms and brilliancy in polarized light. There are 

 indications of crystal form, but on account of the small size nothing further can be determined. The amorphous 

 matter gives no reaction for chromium nor phosphorous and appears to be formed exclusively of graphite like that con- 

 tained in the iron itself. Others of the uncolored grains are remarkable for their fine striations. These are like what 

 I have already noted in certain portions of the stony meteorites and in the fusion of eherzolites. In the latter they 

 occur, not only in the olivine, where they are due to cleavage planes, but also in the enstatite, with its fibrous struc- 

 ture. It should be noted that these hard, hyaline grains, not decomposable by acids, found in the meteorites of Caille 

 and Charcas are not found in the metallic mass but in the troilite nodules. The sulphide of iron thus presents a 

 remarkable contrast to the iron in which it is disseminated. The meteoric iron has no appreciable quantity of sulphur 

 and the sulphide has no nickel. 



After noting all these physical and chemical qualities of Charcas it is superfluous to say that the mass could not 

 be of terrestrial nor artificial origin. Its meteoric origin is as incontestable as is the memory of its fall preserved by 

 tradition. 



