We hear that the enemy left about 100 pieces of cannon at Castle William; but each of them either with a trunnion beat off, or spiked up. Near or quite. all the enemy's fleet lay below the Castle 'till Tuesday last, when a considerable part of them (said to be about one half) put to sea. The remainder (except 5 ships of war) sailed on Wednesday afternoon. The general opinion is, that the enemy's fleet and army, lately fled from Boston, are bound for Halifax. The man of war building at Portsmouth for the Continental service, will, it is said, be ready to launch in about a month.