METEORITE COLLECTION—HANDBOOK AND CATALOGUE, 17 
These are usually present in combination, but hydrogen and 
nitrogen occur as occluded gases and carbon in the elementary form 
of graphite or diamond. 
The following compounds occur, which in chemical composition 
and physical properties seem to be wholly similar to terrestrial miner- 
als of the same name: 
The silicates, chrysolite (Mg, Fe), Si O,, enstatite, Mg Si O,, 
bronzite, (Mg, Fe) Si O,, diopside including diallage, Ca Mg (S1 O,), 
+ Ca (Mg, Fe) (Si O,),, augite, Ca (Mg, Fe) (Si 0,), + (Mg, Fe) 
eer ©, labradorite, (Na Al 5i,-O, +.Ca Al, Si, O,) and 
eerie, Ca Al, 3i,.0,;- the oxides, macnetite, Fe O, Fe, O, and 
chromite, Fe O, Cr, O,; the sulphides, pyrite, Fe 5,, and pyrrhotite, 
Fe, S,, and the carbonate, breunnerite Mg Co, with Fe O. | 
Quartz, (Si O,), though so widely distributed upon the earth, is 
conspicuous by its absence from meteorites, Small crystals have, 
however, recently been observed in the crust of some of the Toluca 
irons,* and free silica occurs in several meteorites in the form of asman- 
ite, a compound believed to be identical with tridymite. Zircon, (Zr Si 
O,) hasalso been found in one of the Toluca masses, and the presence 
of orthoclase, garnet and apatite in several meteorites is probable, 
though not proved. Several soluble salts, such as chloride of sodium, 
and sulphates of sodium, calcium and magnesium, have been found 
in meteorites, and the carbonaceous meteorites contain bituminous 
substances which closely resemble terrestrial bitumens. As occluded 
gases occur marsh gas and carbon monoxide and dioxide. 
The soluble salts and breunnerite are regarded by Cohen as of 
secondary origin, 1. e., formed after the entrance of the meteorite in- 
to the earth’s atmosphere, and the same may be true of the gases and 
bituminous substances. Various other compounds found in mete- 
orites have from time to time been described as distinct species but 
their identity with terrestrial minerals has later been established. 
The following compounds found in meteorites are believed to 
have no representatives among terrestrial minerals: 
Various alloys of nickel and iron, including taenite, Fe, Ni, 
kamacite, Fe,, Ni, plessite, Fe,, Ni, and edmonsonite; chalypite, a 
compound of iron and carbon; cliftonite, a cubic form of graphitic 
carbon; cohenite, (Fe, Ni, Co),C; schreibersite, (Fe, Ni), P; troilite, 
Fe S; oldhamite, Ca S; osbornite, supposed to be a sulphide or oxysul- 
phide of calcium and probably titanium; daubréelite, Fe S, Cr, S,, 
and lawrencite, Fe Cl,. 
The chemical character of these compounds indicates that the 
conditions under which they were formed differed from those which 
*Groth’s Zeitschr fiir Kryst. und Min., Bd. 24. p. 485. 
