METEORITES OF NORTH AMERICA. 235 



shooting stars, principally because the time of the fall of the meteorite, so far as observation reaches, did not coincide 

 with the time upon which the majority of the appearances of the shooting stars appear. Moreover, upon this suppo- 

 sition the great similarity in the composition of the meteoric stones could scarcely be explained. It becomes increas- 

 ingly probable, therefore, that we have to do with fragments of celestial bodies, which originated from a shattering, 

 either by collision or by disruption from some inner cause, whereby the momentum gained preponderance over the 

 original gravitation and the fragments, having come into the range of the earth 's attraction, must fall upon it. Whether 

 they are portions of an asteroidal body, or, as Meunier will have it, of a second earth satellite, remains for astronomical 

 discussion to decide, which is foreign to our subject here. 



Crust. The meteorite in question is covered all over, except for a small artificial abrasion, with a black, slightly 

 wrinkled crust about 0.05 mm. in thickness and with a dull luster. This glassy coating is fissured and may be easily 

 loosened from the mass, portions of the latter being, however, usually removed with it. There are to be seen in the 

 interior of the stone in question no veins of matter like the crust, or smooth surfaces like those which are to be found so 

 plentifully in, for example, the stones of Pultusk. 



This crust, upon closer examination, consists of a scarcely transparent glassy substance which shows single refraction 

 and occasionally incloses bubbles and pores, although not in so marked a manner as in the crust material of the Pultusk 

 stone. The crust is not spread out over the surface of the stone in an entirely uniform manner; in some places meteoric 

 iron particles appear with a metallic luster upon mild rubbing, in other places it is extremely t.hin and of a somewhat 

 brighter color, or again thicker and more shiny. As shown by thin sections, the thin-crusted places correspond to the 

 intrusion of olivine grains into the region of the crust, while where iron sulphide protrudes a thicker fusion crust is found . 



On account of the depth of the coloring it is very hard to obtain the crust in transparent thin sections. This may 

 be attained more readily by crushing small scales between two thin plates of glass. It shows then a deep bottle-green to 

 brownish red color and behaves in polarized light like an amorphous glass. This characteristic confirms the conjecture 

 that the crust was formed by the flight of the mass through the earth's atmosphere, producing a true fusion crust. For 

 comparison, small scales from the interior of the stone were melted before the blow pipe, only in very thin fragments and 

 the molten mass showed exactly the characteristics of the fusion crust, the same color, and the same bubbles. The stone 

 behaved peculiarly when, without melting, it was subjected for a considerable time to a strong red heat. It took on 

 thereby a dark brownish black color, and showed, upon cutting it open, isolated particles, which appeared as if melted. 

 1 1 is these borders of the pyrites which in fact suffered fusion . From thin sections of these heated particles, it is apparent 

 that the greater part of the stone took on a deep brown color from heating, which, as I have elsewhere showed, yields a 

 very good indication of olivine. The black borders of the particles of pyrites are almost opaque, of a deep brown color, 

 and refract the light singly, exactly like the fusion crust. This dark color which the stone takes on by heating, a color 

 which, on the natural stone itself, is never found deep under the fusion crust, indicates that the fusion heat confined 

 its operation to an extremely thin layer of the exterior surface without subjecting the deeper portions of the stone to a 

 higher temperature. In contrast with this phenomenon the veining of many meteoric stones of other localities is very 

 noteworthy. In the case of the Pultusk stone, material from which was at my disposal, I found that these veinlets also 

 consisted of an amorphous glassy substance. Of a similar sort seem to be the black, almost opaque specks which, in 

 many meteoric stones, appear scattered through the entire mass and apparently furnish the borders around the more 

 easily fusible ingredients; for example, pyrites. 



I do not think, however, that the above-mentioned fine veinlets are molten material which has penetrated from the 

 crust into the interior of the stone, but that at such places the stone was cleft or cracked, and that in these cracks, 

 accessible to the atmosphere, the same fusion process by friction took place, just as upon the surface itself. 



Stony mass. The tolerably hard body of this stone, which can not be crumbled between the fingers, consists of a 

 conglomerate of fragmentary particles, which are compacted together without any matrix, since neither a glassy nor 

 other pronounced binding substance is to be seen between the individual grains. Small slivers of minerals with 

 entirely irregular outlines are found in great numbers in the mass of the stone, as if they came from broken crystals or 

 crystalline masses. Only very seldom in thin sections are pieces to be seen, which, being bounded by comparatively 

 straight lines, may pass for small crystals or as ordinary cleavage products. Associated with the above are angular 

 granules, which by their glassy luster and their color are quite readily determined as olivine, whitish particles of an 

 opaque substance, small granules of bluish gray meteoric iron with a metallic luster, tombac yellow, much perforated 

 lumps of iron sulphide whose fine grains sometimes form inclosed masses and ultimately even small rounded, now dark, 

 now bright colored globules which give to the stone the character of Rose's chondrite. Dust-like particles, extremely 

 fine and without metallic luster, are also found scattered or massed in small groups which are related to chrome iron, or a 

 carbonaceous substance, since they offer resistance to every action of acid. 



One of the most notable phenomena in the case of nearly all constituents of a metallic character, is that the 

 individual fragments are penetrated by a surprising number of very fine to extremely fine cracks. In the case of 

 many of the constituents there appears a certain regularity in the direction of these endless rifts, arising from a par- 

 allel direction of the cracks, which presumably bears a relation to the cleavage plane of the mineral in question. But 

 at the same time, other cracks occur, besides those more regularly arranged, which cross the latter at right angles or 

 diagonally, and produce a perfect network of cracks, so that even otherwise bright mineral particles are dimmed 

 thereby. They must be regarded as an indication of shattering produced by concussion, pressure, or sudden change 

 of temperature. 



By reason of this cracked character of most of the constituents, the deeper ulterior character is often so obscured 

 that it is rarely possible to make out, in the larger individual fragments, the apparently prominent bubbles, which, 



