rites that have been
observed seem to have been ushered in by a detonation. We do not,
however, assert that this is quite an invariable feature; and it is also
the case that meteors often detonate without throwing down any solid
fragments that have been collected. The violence associated with the
phenomenon is forcibly illustrated by the Butsura meteorite. This object
fell in India in 1861. A loud explosion was heard, several fragments of
stone were collected from distances three or four miles apart; and when
brought together, they were found to fit, so as to enable the primitive
form of the meteorite to be reconstructed. A few of the pieces are
wanting (they were, no doubt, lost by falling unobserved into localities
from which they could not be recovered), but we have obtained pieces
quite numerous enough to permit us to form a good idea of the irregular
shape of the object before the explosion occurred which shattered it
into fragments. This is one of the ordinary stony meteorites, and is
thus contrasted with the Rowton siderite which we have just been
considering. There are also other types of meteorites. The Breitenbach
iron, as it is called, is a good representative of a class of these
bodies which lie intermediate between the meteoric irons and the stones.
It consists of a coarsely cellular mass of iron, the cavities being
filled with mineral substances. In the Museum, sections of intermediate
forms are shown in which this structure is exhibited.

Look first at the most obvious characteristic of these meteorites. We do
not now allude to their chemical composition, but to their external
appearance. What is the most remarkable feature in the shape of these
objects?--surely it is that they are fragments. They are evidently
pieces that are _broken_ from some larger object. This is apparent by
merely looking at their form; it is still more manifest when we examine
their mechanical structure. It is often found that meteorites are
themselves composed of smaller fragments. Such a structure may be
illustrated by a section of an aerolite found on the Sierra of Chaco,
weighing about 30 lbs. (Fig. 79).

The section here represented shows the composite structure of this
object, which belongs to the class of stony meteorites. Its shape shows
that it was really a fragment with angular edges and corners. No doubt
it may have been much more considerable when it first dashed into the
atmosphere. The angular edges now seen on the e