$94 J. L. Smith—Mass of Meteorie Iron. 
center to the circumference of the crystals, during the slow 
consolidation of the latter. e result of this phenomenon 
would be to destroy the homogenous character of the mass, and 
consequently to render its different parts variously susceptible 
to the action of chemical agents. Thus, an acid would act in 
one part on the iron more readily than in another, affecting the 
least that part containing most phosphorus, even though this 
last element should be in very minute quantity, and so produc- 
ing that mottled surface in the lines of crystallization known 
the Widmanstattian figures. 
Of all examples of the separation of substances in the forma- 
tion of natural compounds, there are none comparable to those 
exhibited by metevric irons, in which elements having a most 
remarkable affinity for each other are separated the one from the 
other by the sharpest possible lines. Of course, I do not mean 
by this that the sulphur, phosphorus and iron of a meteorite 
are completely separated the one from the other, but that a small 
portion of the iron will combine with nearly all the sulphur and 
phosphorus of the entire mass, segregating in clear and distinct 
nodules, and in a manner that it would be vain for us to 
attempt to produce artificially. a 
me of the most remarkable forms of this segregation 18 
where the sulphur and phosphorus compounds are eliminated 
into the same cavity, as was first shown by me in 1852. I 
have in my possession (and the same may be found in other cab- 
inets) several examples of this. The last one which has come 
to my notice is that of the iron which fell in South Africa 
1862, and which I described in a recent number of this Jour- 
nal. In this iron there is an oval cavity, two and a half centl- 
meters in its long diameter; at the center is troilite (sulphid of 
iron), filling the cavity to within one or two millimeters of the 
surface; and between the exterior surface of the troilite and 
the inner surface of the cavity is a thin layer of schreibersite 
{a phosphuret of iron and nickel of definite composition) 
(Ni? Fe‘P), with hardly a trace of sulphur. In other places in 
with layers of schreibersite, the iron itself has remaining in the 
mass only ‘019 of one per cent; and it seems to me impossible 
to explain such perfect elimination of phosphorus and sulphur, 
‘su : ving so strong an affinity, except by supposing ® 
rks 
long plastic condition and slow consolidation of the mass. 
