180 MEMOIES NATIONAL ACADEMY OF SCIENCES, VOL. XIII. 



Chemical analyses from two specimens gave: 



No. 1. 



Silica 49. 50 



Ferrous oxide 15. 88 



Magnesia 33. 01 



98. 29 99. 11 



The oxygen ratios indicate a compound of two atoms of enstatite or bronzite plus one atom of olivine. 



These small fragments (of Estherville meteorite) in the differences of composition and specific gravity, show a 

 hitherto unheard of phenomenon of meteorites of one and the same fall. One of these small masses, for instance, con- 

 sists almost exclusively of iron, with a specific gravity of 7 to 7.3; others are almost free of iron and consist of a granular 

 crystalline mass of olivine, with a specific gravity of 4 to 3. Between these extremes are all variations. The mean 

 specific gravity of 14 specimens is 5.80 and this may be the weight of the larger masses. 



According to Shepard, the small aerolites, with their differing specific gravities, do not originate from the breaking 

 up of larger bodies by its entrance into the earth's atmosphere, but are independent parts of the swarm. \ATiile the 

 pieces of iron are of very irregular, sometimes of jagged form, Shepard describes a small stone with a specific gravity 

 of 3 as a flattened spheroid with distinct Brust and Ruckenseite and also lines of flow which, directed from apex to 

 periphery, indicate the direction of flight. 



Vom Rath 6 gives the following account of the meteorite: 



On account of its mineralogical constitution, the Estherville fall possesses great interest. The stones are of an 

 unusual kind; that is, they are not chondrites. They are further remarkable for the highly granular, crystalline 

 structure and the absence of chondritic spheres. The crystalline grains (olivine) are of extremely various sizes. 

 Besides grains of 1 cm. in size, distinguished by their cleavability, there are others of less than a milimeter in size. 

 The structure is also noteworthy from the fact that hollow spaces and swellings, so exceedingly rare in meteorites, 

 are present, upon whose walls individual very small crystals are to be seen. As olivine forms the largely predomi- 

 nant constituent of two samples almost entirely free of iron, so it appears also in many-sided crystals in the small 

 hollow places. In a granule of about 0.5 mm. in size, rounded like the pallas-olivine, there may be two zones crossed 

 in one face. Besides the olivine, there is also present, as a more subordinate constituent, an almost colorless mineral 

 of a glassy luster, which also occasionally shows crystalline faces. Shepard regards this colorless constituent as a 

 triclinic feldspar, anorthite, an explanation which, however, does not seem free from doubt. According to Shepard, 

 chromite is also present in extremely small quantities. Finally troilite is still to be mentioned as a constituent of 

 the Estherville meteorite. Although the small aerolites of the Estherville fall, so strikingly different in respect to 

 the predominance of olivine on the one hand, and of iron on the other hand, are not to be regarded as fragments of a 

 much larger mass broken up by entrance into the earth's atmosphere, we must still regard both as constituents of 

 meteoric phenomena; as also the larger lumps inclosed in predominant olivine masses are unevenly distributed and 

 irregularly formed iron masses. It is not easy, as Shepard has pointed out, to refer this meteorite to any division 

 hitherto established. If we consider the stones as made up essentially of olivine, the meteorite of Chassigny, which 

 is regarded as the type of a special class, would furnish the nearest comparison, while the masses rich in iron appear 

 to connect themselves with the pallasites. 



Brezina, 8 in 1881, made brief mention of the meteorite as follows: 



Specific gravity of stony portion, 3.36; of metallic portion, 5.97. 



The Estherville stone shows a very beautiful and peculiar crust, although corresponding to the coarse-grained 

 structure in extremely various forms, according as they inclose troilite or the bronzelike groundmass of the iron. The 

 small quantity of peckhamite present does not at all suffice to distinguish this stone from the other mesosiderites. 



Meunier 9 reports his conclusions from a study of the meteorite, as follows: 



In classifying the specimens from this fall, it occurred to me to see whether the rock of which they are composed 

 is new to science or whether it belongs in some of the numerous lithological types already established. 



The result of my researches, very different from what might be inferred from those of Lawrence Smith, is that 

 the meteorite of Emmet County belongs lithologically to the type which since 1870 I have called by the name of 

 logronite, the best-known example of which is procured from the masses of the Sierra de Chaco (Bolivia). It is 

 known, moreover, that the fall of logronite was already witnessed at Barea, near to Logrono (Spain), on July 4, 1842. 



At first Bight the Estherville rock appears to differ distinctly from the logronite type. It is not so dark, and the 

 granules of iron disseminated through it present on the whole a more considerable volume. The result of this latter 

 characteristic is that the mass makes the impression of a pure polysiderite; but upon closer inspection it is possible to 

 discover that with the more or less globular grains of iron are associated thin metallic filaments which bind the whole 

 together and constitute at many points the true cement of the stony elements. This characteristic appears also in the 

 meteorites of Sierra de Chaco and Logrono, which are as much syssiderites as sporadosiderites. 



As to the lighter shade of the Emmet County specimen, in comparison with Logrono and Sierra de Chaco, it may 

 be due to certain coloring matters, infiltrated into these latter, which had not time to originate in equal proportion in 

 the more recently fallen stone. These coloring matters are probably derived, by oxidation, from certain elements of 



