112 On Meteorites. 
play a much greater rôle than we might be apt to imagine, judging 
from the processes which take place on our earth. 
Finally, I may mention that in some meteorites there is found 
evidence of their having been exposed to an enormous heat after 
their original formation. Several meteorites—particularly one 
from Steelldal, Sweden, which I have examined myself—show traces 
of an inner melting which must have taken place somewhere in 
space before entering our atmosphere, and which has nothing to do 
with the ignition of their surface in the latter and the molten crust 
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i 
bal 
f 
Fig. 5. The Stælldal meteorite viewed in microscope. $ Drawn 
by the author. 
thus produced. The appended cut (Fig. 5) shows a portion of the 
Stælldal meteorite sixty-five times magnified. The black parts are 
iron; the light ones are pieces of unmolten substance swimming in 
a brownish glass, the chemical composition of which is like that of 
the unmolten substance. It will thus be seen that in the structure 
of some meteorites we have.a direct proof of their orbits being of 
the same striking form as those of the comets, which alternately 
approach close to the sun and then again recede far from it. 
