We afterwards climbed up by a narrow spiral staircase to the top of the tower, from whence we had a fine view over the whole of the bay and the surrounding shores.  On the summit are the remnants of a lantern which was formerly used as a beacon for the benefit of mariners entering the bay.  This monastic castle, for such it should be called, has frequently been besieged.  On the last occasion it was held by Sir Francis Bassett, for Charles the First, when it was besieged by the Parliamentary forces; but he was at last compelled to capitulate, though as a reward for his bravery he and his followers were allowed to retire to the Scilly Islands.  Altogether, we agreed that it was one of the most interesting spots we had hitherto visited during our voyage.