Happily these acclivities wound up the interior of the volcano and favored their ascent.
As to the volcano itself, it could not be doubted that it was completely extinct.

No smoke escaped from its sides; not a flame could be seen in the dark hollows; not a roar, not a mutter, no trembling even issued from this black well, which perhaps reached far into the bowels of the earth.

The atmosphere inside the crater was filled with no sulphurous vapor.

It was more than the sleep of a volcano; it was its complete extinction.

Cyrus Harding's attempt would succeed.
Little by little, Herbert and he climbing up the sides of the interior, saw the crater widen above their heads.