1032 General Notes. [December, 



per cent, of nickel, with small percentages of cobalt, silicium and 

 copper. Lying on the plates of meteoric iron, which make up the 

 mass, are thin metallic fl xible plates of the thickness of writing 

 paper of a substance having the composition Fe 5 Ni 2 - It is this 

 mineral which forms the figures on etched surfaces, and not, as 

 generally believed, schreibersite. The name lulmonsonite Ts pro- 

 posed for this mineral. 



Nodules of troilite and graphite, and square prisms of what 

 appears to be rhabdite (Fe 4 Ni 3 ) P. occur through the mass. 



Two other minerals were noticed, and are probably new. One 

 occurs as brass-colored oblique crystals, clcavable across the base, 

 and having a composition agreeing with the formula (Fe,, Nb) P-> 

 Another phosphide whose formula was (Fe 7 Nb) P. occurred in 

 square prisms, bright externally, and dull, almost black within. 



The occluded gases in the meteorite amounted in bulk to 3.59 

 times the volume of the iron, and consisted of carbonic acid, 

 0.12 ; carbonic oxide, 31.88; hydrogen, 45.79; marsh-gas, 4.55 ; 

 nitrogen, 17.66. 



Corundum and its Alterations.— Dr. F. A. Genth has made 

 another valuable contribution to our knowledge of the genesis of 

 minerals. in a paper read before the American Philosophical So- 

 ciety, on August, 18, 1882. The paper is in part an appendix to 

 his former paper on corundum and its alterations, and in part a 

 collection of mineralogical notes on various subjects. 



Of the alterations of corundum, the first described is an alteration 

 into spinel of the corundum from Carter mine, Madison county, N. 

 C. When containing fissures, it was observed, sometimes only by 

 a small dark line, that a change had commenced, which, extending 

 sometimes through large: masses, had converted the corundum 

 into a massive greenish-black spinel of granular structure. The 

 spinel finally passes into prochlorite. Particles of spinel were also 

 observed in corundum from Shimersville, Lehigh county, Pa., 

 and were regarded as the result of alteration. At Toures county, 

 Ga., corundum was surrounded by an alteration into greenish- 

 white, cleavable zoisite. 



Several examples are given of the alteration of corundum into 



number of instances are <dv n'of alteration into mica. 

 A specimen from Ilavwood co., N. C, showed a large crystal of 

 muscovite to which albite was attached, while through both sub- 

 stances there occurred remnants of corundum crystals, dissemi- 

 nated through the mass. The particles of corundum are corroded ' 

 as though by a dissolving agent, and the whole mass has the ap- 

 pearance of a coarse granite- in which corundum replaces thequartz. 

 In some specimens from Alabama, the corundum crystals are sur- 

 rounded by a layer of sub-fibrous mica, outside of which is a fine 

 scaly mica, much of which has changed into brown scales, which 

 exfoliate when heated. The corundum is rounded and corroded, 



