METEORITES OF NORTH AMERICA. 165 



All three of the samples examined by Brezina and Cohen * (consisting of a portion of No. I, weighing 1,054 grams 

 and measuring 135 cm. ; a portion of No. Ill, weighing 570 grams and measuring 75 cm. ; and a portion of No. VI, weigh- 

 ing 243 grams and measuring 38 cm.) are characterized by abundant schreibersite in elongated, twisted individuals 

 with hook or loop like conformation. In respect to the size and manifold form of the schreibersite. De Sotoville exceeds 

 all known meteorites except Primitiva. Other shapes and forms resembling hieroglyphics also occur. Rhabdite 

 also occurs, sometimes isolated, but mostly compacted together in groups, and then in a twofold formation and arrange- 

 ment. In many places the needles attain a length of 3 mm. ; they appear to be arranged according to three directions, 

 so that two of these intersect at an angle of 90, and the third runs diagonally. Their occurrence in layers separated 

 some 1.5 cm. from one another, is extremely various, as well as the lengthening of the latter. Sometimes they traverse 

 completely a large plate, sometimes they can be followed only for a short distance. Schreibersite is entirely wanting 

 for some distance, where rhabdite accumulates in larger quantities. Finally, in many places near the natural exterior, 

 giant rhabdites occur; these are from 0.05 to 0.15 mm. wide and as much as 2 cm. long, and sometimes lie parallel to 

 one another; sometimes they intersect at various angles, apparently without regularity. Should there occur here 

 also a regular orientation, still there is another as in the case of the elongated rhabdites. 



Most of the giant rhabdites remained rough and lusterless after etching, as if not entirely unchanged. All the 

 rhabdites are surrounded with a highly lustrous etching zone, a feature which is the exception in the case of the large 

 schreibersites and then only on portions of the crystals. 



It appears to be the giant rhabdite which Foote mentions as the " pyritiferous mineral"; on the contrary, how- 

 ever, the analyses sometimes show no sulphur at all, and only small masses of it at most in other cases. At all events, 

 iron sulphide has not been observed in visible particles, which, considering the size of the cut surfaces examined, 

 appears quite remarkable. 



" Eisenglas" frequently occurs on the edge of the plates, and this usually incloses and sometimes penetrates large 

 schreibersites. After dislodging the crystals there remains a thin black film clinging to the nickel-iron; it is partially 

 covered over with a brown coating, wEich, contrary to expectation, gives no chlorine reaction. 



Brezina and Cohen * give the following analysis of the schreibersite from carefully selected material: 



Fe Ni Co P Residue. 



71.70 12.58 0.32 15.45 0.15 =100.20 



Accordingly this schreibersite belongs to the variety which contains the least nickel of any yet investigated. It would 

 be interesting also to determine whether the rhabdite, as usual, is here characterized by a higher content of nickel. 



While the accessory ingredients and their occurrence are the same in all three masses, the structure is so divergent 

 that a separate description seems to be desirable. 



In the case of No. I. after moderate etching, densely compacted Neumann lines appear, which are of such fine- 

 ness as scarcely to be noticeable to the naked eye; under the glass, however, they appear with extraordinary distinct- 

 ness. From the various line systems a few are distinguished, as usual, by greater length than the others, but not by 

 a corresponding depth and breadth, as is usually the case in other hexahedrites. As a rule, the etching lines contrast 

 sharply with the large schreibersites, and only occasionally is a slight faulting observed. Disregarding the latter 

 purely local phenomenon, the former extends with similar orientation over the entire surface of the section. At this 

 stage of the etching, the etched surface takes on such a bright, atlas-like sheen that portions with stronger or weaker 

 reflection may be distinguished, which, by turning the plate, gradually pass into one another. The difference in 

 the behavior of individual portions in direct light seems to be due to the fact that in places only Neumann lines are 

 present, while on other portions etching pits occur which gradually increase in number and thus render the lines 

 indistinct. At all events it is easy to see that an oriented luster can only be conditioned by etching lines, and that 

 the occurrence of etching pits does not increase the distinctness of this sheen. This is easily explainable also, since 

 the pittings are bordered by hexahedral facets, but the surfaces laid bare by the etching out of the twin lamella: run 

 in different directions, and now one and now another reflection will determine the sheen. By further etching, the 

 lines and pits become broader and deeper and new etching lines seem to be added; finally, the smooth, lustrous little 

 areas between the Neumann lines become rounded lumps, the entire etched surface takes on a rippled, lumpy appear- 

 ance, and the former strongly and uniformly oriented sheen now becomes dull because of diffuse reflection. Adjacent 

 to the schreibersite the hexahedral iron shows numerous etching zones 0.3 to 0.5 mm. wide, upon which, after etching, 

 the iron remains bright gray, while it becomes dark gray at a distance from the schreibersite. The same thing occurs 

 in the neighborhood of the rhabdite. 



If it be concluded from the regular course of the Neumann lines and from the compact, parallel layers of rhabdite, 

 as well as from its orientation within the layers, that the entire mass is an individual of the structure of a hexahedrite, 

 this result becomes established if a plate be half cut through and then broken. The fractured surface leaves signs of 

 cleavage which are oriented in three directions perpendicular to one another. Larger continuous cleavage surfaces 

 are entirely wanting, since the division usually takes place along the borders of the schreibersite and the cleavage is 

 thereby interrupted. 



The etched surface of No. VI shows a silken sheen which here, however, appears peculiarly burnt, as in the case of 

 Primitiva. The Neumann lines almost disappear; they can only be seen under a strong glass and then are confined 

 almost entirely to those portions of the nickel-iron which lie in the vicinity of large schreibersites or are enveloped in 

 growth forms of the same. Besides or instead of the etching lines, fine, short, slightly crumpled cracks occur everywhere 

 and run parallel to one another and in the main parallel to the direction of the velvety sheen. Very fine, straight Neu- 

 mann lines appear whose breadths have been determined under the microscope as 0.003 to 0.004 mm., running prin- 



