METEORITES OF NORTH AMERICA. 281 



The weathering which the mass has undergone since its advent upon the earth has affected it considerably. Even 

 the larger fragments when broken open will be found to be deeply invaded by rust which has penetrated along 

 cracks in every direction. Doubtless the great number of small fragments into which the stone was found to be 

 broken when first discovered was due to this process of separation through weathering rather than to shattering caused 

 by the blow of the mass upon the earth. The weathering has affected chiefly the metallic constituents of the stone, 

 causing their oxidation, and this rust has penetrated and stained the meteorite deeply. The color of the weathered 

 surfaces has thus been changed from the dark green of the unaltered rock to various shades of brown, a characteristic 

 color being a light yellowish-brown, almost white, spotted with dark or rust brown. 



The depth to which this discoloration has extended, except where it has followed cracks and fissures, is usually 

 scarcely a millimeter, the color changing beyond this through reddish to black before the dark green of the unstained 

 stone is seen. 



Over a large part of the surface of the stone as found appeared a white amorphous coating which adhered very 

 firmly. It could be removed by treatment with weak acid, and most of it has been taken off in this way since the 

 arrival of the stone at the museum. When its substance is examined chemically it is found to be carbonate of lime 

 containing a small percentage of clay. There can be little doubt that this coating is derived from the calcareous soil 

 in which the stone lay for an unknown period, the carbonate of lime from the soil doubtless spreading over the meteor- 

 ite surfaces through capillary attraction and cementing upon the stone some of the surrounding clay. In some cavi- 

 ties of the stone a much greater proportion of soil is held, and at many points the cementing agent is iron oxide, 

 derived doubtless from the oxidation of the metallic grains of the meteorite. 



The unaltered stone, when exposed by fresh fracture, is of a dark-green color, varying to black, although the latter 

 shade may be due to staining from terrestrial oxidation. The stone is fine grained, tough, and compact. Occasional 

 portions exhibit a slight porosity, giving a slaglike appearance. Such areas are, however, small and the pores of small 

 size. The proportion of metallic ingredients is not large but they are quite uniformly distributed. 



The metallic grains show most plainly on a polished surface, the distribution and quantity being illustrated in a 

 figure. Occasionally well-marked aggregations of these may be seen. None of the surfaces that I have examined 

 show arrangement of the grains in lines or systems of lines such as have been noted in a number of stone meteorites 

 by Reichenbach and Newton. The largest metallic grain I have seen in the Long Island meteorite has a diameter of 

 1.5 mm. From this size all gradations may be found down to the minutest grains, examination with a lens bringing 

 out many not visible to the naked eye. 



The bronze-yellow color and comparative softness of many of the grains as exhibited on a polished surface mark 

 them as troilite, in conU-ast to the silver-white color and greater hardness of those composed of nickel-iron. Further 

 identification of the grains can be obtained by isolating them or by treating a polished surface of the meteorite with 

 copper sulphate. On the polished surfaces examined the number of troilite grains is evidently much in excess of those 

 of nickel-iron. As individual grains they are, however, smaller in size. Often the nickel-iron and troilite can be seen 

 to be intergrown in a single grain. 



Before the blowpipe a fragment of the rock fuses, even in the oxidizing flame, with a fusibility of about 4.5, the 

 entire fragment blackening from the formation doubtless of FeO. In the reducing flame the fusibility is, as would be 

 expected, greater on account of a more rapid formation of FeO. Evidently the mixture of minerals forms an aggre- 

 gate fusible at a lower temperature than any of its components, for the component minerals are practically infusible. 



The specific gravity of the stone, determined as an average of three separate portions weighing 50, 18, and 7 grams, 

 respectively, is 3.45. 



To the observations of Weinschenk [regarding the petrographic characters of the meteorite] there is little of 

 importance to be added. The crystalline structure is perhaps hardly as prominent megascopically as one would 

 judge from Weinschenk's account, while the chondritic structure is easily recognized in all the sections I have 

 examined. There are numerous polysomatic porphyritic chrysolite chondri and typical fibrous ones of enstatite. 

 One of the latter observed was 2.5 mm. in diameter, and it is evidently not cut through its center. A black, 

 seemingly carbonaceous matter borders its outer edge. The fibers are minute and lie in parallel groups extending 

 in various directions. A porphyritic chrysolite chondrus seen had a diameter of 1.25 mm., a single grain reaching 

 the size of 0.025 mm. Another monosomatic chrysolite chondrus seen was made up of chrysolite porphyriticall v 

 developed in glass and with a distinct circular border of chrysolite all extinguishing simultaneously. This chondrus 

 also contained a large grain of troilite. The crystal outlines of the chrysolite individuals, whether developed in 

 the chondri or out, are often well defined, the predominant habit being short stout crystals bounded chiefly by 

 pinacoids. The chromite more often has a red tone than the brown described by Weinschenk, its deep red grains 

 being frequently seen in the sections. Both nickel-iron and troilite grains sometimes inclose small siliceous particles 

 of what is probably chrysolite, indicating the latter to be the earlier formation. 



As regards classification, the Long Island meteorite is classed by Wulfing aa a crystalline spherical chondrite, 

 Cck. Beaver Creek, Bethlehem, Lumpkin, Menow, Prairie Dog Creek, Richmond, and Savtschenskoje are other 

 meteorites included in the same class. 



Brezina classifies Long Island as a crystalline chondrite Ck., in which group are included Erxleben, Klein- Wenden, 

 Kernouve, and many others. By Meunier, Long Island is put in class 34, Erxlebenite, which includes monogenic 

 meteorites of fine grain made up chiefly of chrysolite and bronzite and containing visible grains of nickel-iron. Bluff, 

 Erxleben, Kernouve, Klein-\Venden, Menow. and Pipe Creek are among the other meteorites brought by Meunier 

 into this class. Thus the place of Long Island in classification seems to be quite generally agreed upon. Differences 



