METEORITES OF NORTH AMERICA. 187 



than the analysis shows, since the inclusions dissolved in HC1 would influence the result. Of other minerals a rhombic 

 pyroxene can be observed which often shows almost fibrous cleavage and seldom has definite boundaries; also mono- 

 symmetric augite can be observed. Both these minerals are poor in inclusions and form radiating clear chondri. 

 Feldspar may be present in the groundmass but was not found among the larger ingredients. Occasionally occurs the 

 mineral designated by Tschermak as "monticellitelike" formed in the usual way. This contains rounded colorless 

 inclusions with bubbles, probably of glass. The chondri appear as usual so that there is nothing to be said of them. 

 The most various forms occur side by side. A glassy base is not present. The stone is rather completely crystalline. 

 The iron veins appear under the microscope to be bounded by a network of a dark brown to black glassy substance 

 which surrounds the flakes and extends pretty deeply into the adjoining mass. The meteorite of Washington belongs 

 to the black chondrites and resembles most the meteorite of Sevrukof. It is moreover a veined black chondrite. 

 According to its macroscopic and microscopic appearance it belongs to those meteorites which are certainly not poly- 

 genic tuffs, but cooled suddenly from a hot mass. What the conditions were that produced the features of rapid 

 crystallization, yet gave the appearance of a completely crystalline stone, we can not now state. 



In a later article which repeats many of the above statements, Kunz and Weinschenk 3 

 recorded the find of a distinct mass weighing 9 pounds on the farm of John Windhurst. 

 Brezina 5 has the following notes on the meteorite : 



Farmington, which has a certain superficial resemblance to Mackinney, is distinguished from the latter by its 

 porous character which extends to the formation of large druses (mostly lined with troilite crystals and crystal fragments) 

 and by a richness in iron in some portions in place of the abundant troilite of the Mackinney mass. The fusion crust 

 is very scarce on the Farmington mass, only remaining in isolated warts the size of millet seeds. In one place along 

 the natural crastless exterior may be seen a broad black crust infiltration reaching to a depth of 3.5 cm., in which run 

 numerous finely branched cracks for the most part filled with nickel-iron. One of these cracks is laid bare for a distance 

 of 15 mm. and does not have the appearance of an armor face, but that of a crystalline tin-white metal plate. Another 

 piece shows a crevice 1 mm. wide which traverses the entire piece and is lined with troilite crystals. A roundish 

 hollow space 1 cm. in size is lined with rounded nickel-iron crystals. A small piece shows on a fractured surface a 

 black crystal 1 cm. long of a pyroxene mineral with two cleavage planes almost perpendicular to each other, also a grain 

 of a white monticellitelike substance. A troilite outcrop in another piece bears an imprint of half spherical form with 

 even, glistening faces on the bottom. 



In contrast to Mackinney the chondri are not very abundant. They are either leek-green or olivine color. In 

 part they show a greenish-white coating 0.5 mm. in thickness, sharply separated from the interior, but running out 

 into the surrounding groundmass on the exterior. Monticellite-like chondri occur. 



Meunier 6 remarked the metal veins as follows : 



One specimen on the Paris museum is remarkable for the almost capillary veinlets of metal alloy having an intimate 

 analogy with the accidents of many metallic veins and contrasting absolutely with the structure which results in the 

 case of terrestrial rocks of volcanic formation. 



Preston 4 described metallic veins occurring in the meteorite as follows : 



Several sections of the 136.25-pound mass of this meteorite, resembling dark gray conglomerate, show numerous 

 small patches or grains of iron scattered through it, the largest of which is 11 by 6 mm. In the corner of three of these 

 slices there are several veins or fissures extending from 10 to 75 mm. from the edge toward the center, some of which 

 are filled with iron for 65 mm. in length from the edge of the slice inward and measuring 1 mm. in width. On the 

 opposite end of the slice there is a very narrow vein about 90 mm. long which for the greater part of the way is filled 

 with iron. Beyond the larger nodule mentioned the iron is scattered rather evenly throughout the mass in compara- 

 tively small grains. 



The following suggestion as to the origin of the veins was made by Preston : 



That as the meteor struck our atmosphere the concussion was so great that the mass was fractured in various places, 

 of coarse extending from the surface inward, and the larger of these fissures or fractures were then filled by the metallic 

 iron which was fused on the exterior surface of the mass due to its velocity through the atmosphere, and waa thus 

 forced in a molten state into its present position, thus forming the metallic veins. 



This explanation was questioned by Farrington. 7 His conclusion was that the veins were 

 phases of structure of the metallic constituents of the mass, his objections to Preston's view 

 being the following: 



First. The interior of a meteoric mass of any considerable size is so cold that portions of molten metal would be 

 chilled before penetrating to any appreciable distance. Second. The metallic constituents of the Farmington meteorite 

 are its least fusible ones. 



The meteorite is distributed, the Field Museum possessing the largest amount (23.5 kg.). 



