420 J. L. Smith—Concretions in Meteoric Irons. 
with troilite. It is never crystalline in structure like that im 
the interior of cast iron; it is quite like the graphite of Cum- 
berland, England. On treatment by ether or petroleum spirits,. 
a minute quantity of a crystalline substance is dissolved, that 
will be referred to later on as mixed with su 
Daubréelite—This is one of the most interesting concretion- 
ary products in meteoric iron. I discovered it in 1875, in the 
Butcher meteorites; and since then I have found it in other 
meteorites, but so finely divided and mixed through troilite 
nodules that it would have escaped notice altogether had it 
not been for its very marked and prominent mode of occur- 
rence in the above mentioned meteorites. 
Being easily separated from the iron, I was enabled to study 
its properties thoroughly, and thereby furnish a process by 
which it could be detected in other meteorites when completely 
obscured from the eye. 
his mineral occurs in the Butcher meteorites in the manner 
already fully described.* It is commonly associated with 
troilite: but the lines of demarcation are so distinct that par- 
ticles of the pure mineral are mechanically detached without 
difficulty. Its composition is now well known to be FeS+ €15,, 
being analogous to terrestrial chromite, with the oxygen of the 
latter replaced by sulphur. There is no terrestrial mineral of 
the same composition.t Full details of its mineral characteris- 
tics, chemical composition, ete., are found in a previous publica- 
t 
which is at present in the Mineralogical Museum of the Gar < 
eo. 
of Plants at Paris In mass it is perfectly black; in sma 
fragments under the microscope it is translucent and of a dar 
ruby color. This translucence of chromite was first noticed & 
few years ago by an assistant of M. Fouqué of the College of 
France. 
Lawrencite.—This mineral, so-called by M. Daubrée, I first 
found in the Tazewell meteoric iron as described by me 
1858,§ and still later in the Rockingham iron. It is 4 solid 
green protochloride of iron with probably nickel. The quan 
tity obtained was small and could not be analyzed. 
* Comptes Rendus de |’Acad. des Sciences, 1876. 
+ This Journal, vol. xvi, Oct., 1878, will be found a full and complete account, 
analyses, etc. 
Comptes Rendus de |’Acad. des Sciences, 1881]. 
d This Journal, vol. xix, p. 151, 1853. 
