But this observation at so critical a time first disclosed it.

The crew were naturally alarmed.

Here was evidence that, in the great ocean, common laws were not to be relied upon.

But they had great respect for Columbus's knowledge of such subjects.

He told them that it was not the north which had changed, nor the needle, which was true to the north, but the polar star revolved, like other stars, and for the time they were satisfied.
The same day they saw weeds which he was sure were land weeds.