It was the dog of the engineer, Cyrus Harding.

But he was alone! Neither Neb nor his master accompanied him! How was it that his instinct had guided him straight to the Chimneys, which he did not know?
It appeared inexplicable, above all, in the midst of this black night and in such a tempest! But what was still more inexplicable was, that Top was neither tired, nor exhausted, nor even soiled with mud or sand!--Herbert had drawn him towards him, and was patting his head, the dog rubbing his neck against the lad's hands.
"If the dog is found, the master will be found also!" said the reporter.
"God grant it!" responded Herbert.

"Let us set off! Top will guide us!" Pencroft did not make any objection.

He felt that Top's arrival contradicted his conjectures.

"Come along then!" said he.
Pencroft carefully covered the embers on the hearth.