The prolonged absence of the Negro made Pencroft very uneasy.

It was to be feared that he had met with an accident on this unknown land, or that the unhappy fellow had been driven to some act of despair.

But Herbert drew very different conclusions from this absence.

According to him, Neb's delay was caused by some new circumstances which had induced him to prolong his search.
Also, everything new must be to the advantage of Cyrus Harding.

Why had Neb not returned unless hope still detained him?
Perhaps he had found some mark, a footstep, a trace which had put him in the right path.
Perhaps he was at this moment on a certain track.