434 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. XXXIV. 
calls attention to the possible presence of Oldhamite, which, though 
not visible in the thin sections or in the mass, is suggested by his 
qualitative and micro-chemical tests. 
While working over some fragments of the Allegan aerolite with 
especial reference to the separation of its chromite and schreibersite 
contents, it was noticed that certain portions gave, while being 
treated, a marked evolution of hydrogen sulphide under conditions 
that led to the belief that some sulphide other than troilite was 
present. 
Acting upon this, a portion of the fine powder was carefully freed 
from all magnetic particles and analyzed with the following results: 
Cs RY is A Eee a ee a EE Ro ae aR ne nae 9. 12 
Re ae eae TA Se Pa a SONG, PE 6 Sa tea ety an 7. 30 
SO es oS Feo oI Se i oe ect ee 39. 95 
AsO 2 ak eae Se Se EE it EOE ee re ae 0. 09 
LEN Mele Pe Me Toh aps ge pale en Ne rao eI oT aety | 14. 40 
ii Re Q Nani Ook ap ananahe er Meme te ean Meena mle cei ech St Ee 29. 40 
which may be calculated to an olivine-enstatite mixture with 16.66 
Res cent of calcium sulphide. 
An analysis of another fragment of the meteorite, in 2 bth only . 
the calcium and sulphur were *disienim mad gave: 
a result that is in close agreement with the figures required for cal- 
clum sulphide. : 
In most of the previous descriptions of the occurrence of calcium 
sulphide in meteorites attention is called to its honey-yellow to red- 
dish-brown color, when freed from incrusting calcium sulphate, and 
to its nodular form. The material here described was entirely free 
from sulphate. Exposure to strong sunight or to burning magne- 
sium did not cause a visible phosphorescence. It did. not occur in 
nodules having a honey-yellow to chestnut-brown color and all at- 
tempts on my part to distinguish it under thé microscope failed. 
Doctor Merrill,* who made a complete petrographic examination of 
the meteorite, tells me that he found nothing that resembled old- 
hamite. 
It is not possible to describe the appearance of this calcium sul- 
phide except by saying that neither macroscopically nor micro- 
scopically is it to be distinguished from the dust-like ash-gray inter- 
stitial material of the groundmass. It is present in aggregations of 
very fine grains in certain portions of the Allegan stone, but the great 
friability of the meteorite and the extreme difficulty of determining 
the mineral character of the interstitial material of the groundmass 
renders its recognition almost impossible. 
“Proce. Wash. Acad. Sci., 1900, II, pp. 41-56. 
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