On our return on board, the first mate told the captain that a strange brig had come into the harbour and anchored near us--that soon afterward Manuel Silva was seen holding some communication with the people on board.  In a little time a boat came off from her, and after some conversation with a man in the boat, he said that he must bid us good-bye.  No persuasions the mate used could induce him to stop, and he stepped into the boat, and nothing more had been seen of him.  We were very sorry to lose him, and it struck us at the time, I remember, that there was something mysterious in his way of departure.