xterior may be due to an
explosion which then occurred; but this will not account for the
structure of the interior. We there see irregular pieces of varied form
and material agglomerated into a single mass. If we would seek for
analogous objects on the earth, we must look to some of the volcanic
rocks, where we have multitudes of irregular angular fragments cemented
together by a matrix in which they are imbedded. The evidence presented
by this meteorite is conclusive as to one circumstance with regard to
the origin of these objects. They must have come as fragments, from some
body of considerable, if not of vast, dimensions. In this meteorite
there are numerous small grains of iron mingled with mineral substances.
The iron in many meteorites has, indeed, characters resembling those
produced by the actual blasting of iron by dynamite. Thus, a large
meteoric iron from Brazil has been found to have been actually shivered
into fragments at some time anterior to its fall on the earth. These
fragments have been cemented together again by irregular veins of
mineral substances.

[Illustration: Fig. 79.--Section of the Chaco Meteorite.]

For an aerolite of a very different type we may refer to the
carbonaceous meteorite of Orgueil, which fell in France on the 14th May,
1864. On the occasion of its descent a splendid meteor was seen,
rivalling the full moon in size. The actual diameter of this globe of
fire must have been some hundreds of yards. Nearly a hundred fragments
of the body were found scattered over a tract of country fifteen miles
long. This object is of particular interest, inasmuch as it belongs to a
rare group of aerolites, from which metallic iron is absent. It contains
many of the same minerals which are met with in other meteorites, but in
these fragments they are _associated with carbon_, and with substances
of a white or yellowish crystallisable material, soluble in ether, and
resembling some of the hydrocarbons. Such a substance, if it had not
been seen falling to the earth, would probably be deemed a product
resulting from animal or vegetable life!

We have pointed out how a body moving with great velocity and impinging
upon the air may become red-hot and white-hot, or even be driven off
into vapour. How, then, does it happen that meteorites escape this fiery
ordeal, and fall down to the earth, with a great velocity, no doubt, but
still, with very much less than that which would have sufficed to drive
th