1887] Mineralogy and Petrography. 73 
is existence through it of a hole measuring five-eighths of 
n di ter at its narrowest part. Its composition is 
ae P—o0.16; Co and Ni= 8.62; thus belonging to 
the class holosiderite of Brezina. The second mass is Tom 
Laurens Coun Its composition, as determined by 
J-B. Mackintosh, is as follows: Fe= 85.33; Ni = 13.34; Co 
See $e ie O. 16. The Widmanstattian lines indicate a regu- 
lar crystallization. The presence of occluded hydrogen and little 
masses of ferrous chloride (lawrenceite) in its mass render this 
meteorite exceedingly interesting. In the October number the 
same author’ describes a meteor found at Fort Duncan, Maverick 
County, Texas. It weighs ninety-seven and a quarter pounds, and 
contains 94.90 per cent. Fe; P=0.23; Ni and Co=4.87. Sp. 
gr. = 7.522. Its peculiarity is the development in it of two series 
of very fine lines crossing each other at an angle of 70°. Since 
the publication of the article? on the three masses of meteoric iron 
Mr. ae sg Ea the seventh piece aa this Poa yielded, — 
Cu Zn Cr&M C S Si 
88. 376 9.86 der 0.03 0.03 aces 0.41 oi 0.01 0.04 
The crystalline structure of meteoric irons has been well 
worked out by O. W. Huntington,*: who examined the collection 
of these bodies belonging to Harvard College. By a very careful 
investigation of the appearance of the Widmanstattian figures on 
cleavage faces of the different ppano and by comparison of 
similar appearances in the case of many minerals, which, during 
as crystallization, extruded various impurities (as, for instance, 
micas comatung magnetite), Mr. Huntington is led to 
le 
to the principal planes of symm etry in the isometric system; (II.) 
that the Widmanstattian figures and Neumann lines are sections 
of planes of crystalline growth parallel to the three planes men- 
tioned; and (III.) that the features of the Widmanstattian figures 
are due to the elimination of incompatible material during the 
process of crystallization. The results of the investigation 
strengthen the belief that meteoric irons were thrown off from 
the sun or one of the fixed stars, and that they have cooled very 
slowly, while revolving in a zone of intense heat———A meteoric 
gd found in Utah, between Salt Lake City and Echo, accord- 
ing to Messrs. E. S. ‘Dana and S. L. Penfield,5 appears under the 
microscope to consist of spherules of olivine, some of which have 
a distinct coarsely fibrous structure in consequence of the inclu- 
: a F oo Sci., Oct. 1886, p. 304. 
G. F zib. TIL. xxx. Aa 235; of. American Naturalist, Dec. 1885, p. 1214. 
3 Ib., . 1886, 4 Ib., IIL., xxxii., One 1886, p. 284. 
5 piga or, Sci., ek bet. 1886, p. 226. 
