METEORITES OF NORTH AMERICA. 363 



Reichenbach 2 emphasized the fineness and regularity of the Widmannstatten figures, 

 saying: "Putnam appears as fine as the grain of pear wood on the side of the mirror." He 

 mentions also pale-blue plessite, infrequent combs, absence of swollen kamacite, bronze-colored 

 iron sulphide, and iron glass. 



Rose 3 called attention to the regularity, fineness, and beauty of the figures and noted the 

 presence of troilite mixed with nickel iron. 



Brezina 5 gave the following observations : 



Putnam is especially rich in combs which are definitely distinguished from the system of bands. The troilite 

 frequently has daubreelite bands parallel to one another. The troilite is crystallized in hexagonal pyramids and the 

 daubreelite laminae lie parallel to their bases, as I first observed them in Coahuila. 



Huntington 6 gave a figure of an etched octahedron broken out from the Putnam County 

 meteorite. He states : * 



This iron appears, by oxidation of the surface, to break up into octahedrons and acute rhombic prisms. The 

 octahedron represented in the figure was so loose in its structure that it was necessary first to mount it in pitch before 

 grinding the face in order to prevent the plates from splitting off. Here the character is much the same as in De Kalb 

 except that the plates are smaller and at points the iron is perfectly granular, showing no signs of crystallization. 

 Moreover, the groundmass, instead of containing the combs above mentioned, has been broken up by a series of irregular 

 cracks into coarse grains very much like a mass of crackled glass. 



Meunier 7 note the following : 



This iron is entirely analogous to that of Charlotte, with still more abundant plessite. The taenite frequently 

 forms needles broken in two parts which meet at an octahedral angle. 



A specimen in the Paris Museum shows a figure very strongly etched upon which are very distinctly visible several 

 somewhat irregular laminae of schreibersite. Outside of this figure appear grains of pyrrhotine showing crystal- 

 line markings and several lamina? of daubreelite. 



Brezina 8 in 1895 remarked that Putnam resembled Buckeberg, but showed somewhat less 

 puffy kamacite. 



Cohen 10 gave the following observations : 



The lamellae are long, straight, isolated or crowded together, sometimes granular and not puffy. The taenite seams 

 are very distinct, fields well represented and quite prominent. Brezina states that the kamacite is hatched, but I have 

 on two sections of very different crystallographic orientation and under various degrees of etching observed no trace 

 of hatching. On the contrary there has been an exceptionally uniform fine-grained structure (grains scarcely 0.003 

 mm. in size). In consequence of this the luster in reflected light is merely dull. A small portion of the fields, including 

 a few of the larger as well as the smaller, consist of dense, very dark plessite which under a high magnifying power 

 reveals a few tiny uniformly distributed spangles. The predominant fields are brighter and are composed of grains 

 measuring at most 0.15 mm. in size, irregular in form, reflecting simultaneously, and sharply defined from one another. 

 They contain roundish tcenite disks as much as 0.02 mm. in size quite uniformly embedded throughout the parent grains. 

 These grains, which are sometimes roundish, sometimes walnut-shaped, and again quite irregular in form, show again 

 in their turn a fine-grained structure and resemble exactly the kamacite of the bands. There is no repetition of the 

 structure on a large scale, however, since no trace of taenite border bands and small fields crowded between was observed. 

 The fine dark veins which apparently divide the grains consist of slightly-etched grooves. A field is sometimes found 

 which is composed of complete lamellae and a little dense plessite compacted between them. The latter are consider- 

 ably more soluble in acid than the granular portions and accordingly the fields filled with it after strong etching appear 

 considerably deepened. 



Schreibersite appears to be sparingly present in macroscopic particles. It was only observed in a few small grains; 

 in the neighborhood of the natural surface some magnetite is present. 

 Analysis by R. Knauer and O. Berger: 



Fe Ni Co Cu Cr S P 



90.28 7.89 0.79 0.07 0.17 0.25 0.11 =99.56 

 Composition: 



Nickel iron 98. 69 



Schreibersite 0. 72 



Daubreelite 0. 47 



Troilite 0. 1 1 



100. 00 

 Putnam takes on strong permanent magnetism; 9 the specific magnetism was determined by Leick at 2.40 absolute 

 units per gram. 



