experiments
do not, perhaps, disprove the existence of iron in the diamond, but
they do establish the fact that, if iron does exist in an oxidized
state, the quantity is infinitesimally small.
One
more theory of the deposit of diamonds in the South African fields is
deserving of special mention, more for the purpose of showing to what
heights of imagination the human mind may soar, than for any scientific
value it may have. This is an assumption that the diamond deposits came
from a fall of meteors, "a direct gift from heaven," and was first
advanced to notice, it is said, by Meydenbauer. Such a theory seems
highly fantastic and is the most improbable of all. The occasional
inclusion of black diamonds in meteorites is well attested, but these
occurrences are very far from accounting for the formation of the South
African diamond-bearing deposits. " Bizarre as such a theory may
appear," says Sir William Crookes, " I am bound to sav there are many
circumstances which show that the notion of the heavens raining
diamonds is not impossible." The "Ava" meteorite which fell in Hungary
in 1846 contained graphite in cubic crystalline form which G. Rose
thought was produced by the transformation of diamonds. Later
Weinschenk found transparent crystals (diamonds) in the Ava meteorite.
Since
it became known that diamonds (infinitesimally small, it is true, but
nevertheless diamonds) occur in meteorites, a general search has been
made for the minute crystals in meteorites from Australia and Russia,
and from Canon Diablo, Arizona, and diamonds and graphite have been
found.1
From
the above facts and from observations which Sir William Crookes made
at Kimberley, he concludes that the genesis of the diamonds found in
the South African mines was by crys-1 Sir William Crookes's lecture.
