measurement. The combined bulk of these minor
planets is believed to be but a fraction of that of the
earth.

Olbers's explosion theory, long accepted by astronomers,
has been proven open to fatal objections. The
minor planets are now believed to represent a ring of
cosmical matter, cast off from the solar nebula like the
rings that went to form the major planets, but prevented
from becoming aggregated into a single body by the
perturbing mass of Jupiter.


The Discovery of Neptune

As we have seen, the discovery of the first asteroid
confirmed a conjecture; the other important planetary
discovery of the nineteenth century fulfilled a prediction.
Neptune was found through scientific prophecy.
No one suspected the existence of a trans-Uranian
planet till Uranus itself, by hair-breadth departures
from its predicted orbit, gave out the secret. No one
saw the disturbing planet till the pencil of the mathematician,
with almost occult divination, had pointed
out its place in the heavens. The general predication
of a trans-Uranian planet was made by Bessel, the great
Konigsberg astronomer, in 1840; the analysis that revealed
its exact location was undertaken, half a decade
later, by two independent workers--John Couch
Adams, just graduated senior wrangler at Cambridge,