The most famous place on the Dee is Threave Castle, standing on an islet formed by the river not far from Castle Douglas. It was built by Archibald, called the Grim, third Earl of Douglas, and was the scene of one of the terrible crimes which brought about the ruin of that proud house. William, the eighth earl, had imprisoned there Maclellan, tutor (or guardian) of Bombie, whose relative, Sir Patrick Grey, having procured an order for his release from James II., therewith repaired to the castle. Douglas, knowing very well what he came about, with pretended courtesy refused to receive any message till the guest had dined. Whilst Grey was eating with what appetite he might, the prisoner was led forth and beheaded in the courtyard. Dinner over, Grey produced the royal warrant, which Douglas read with mock respect and consternation. Taking his guest by the hand and leading him to the window overlooking the courtyard, he showed him the bleeding corpse. "There lies your sister's son," quoth he, "he lacks the head, but the body is at your service." Grey dissembled his rage and grief till he was in the saddle, when, turning on the mocking earl, he solemnly vowed his heart's blood should pay for that day's work. "To horse! to horse!" cried the enraged tyrant. The pursuers followed Grey for many a long league, nor did they draw bridle till the Castle-Rock of Edinburgh loomed on the horizon. A few months after, the king stabbed Douglas at a conference at Stirling, and Grey avenged Maclellan by killing the wounded man with a pole-axe. In 1455 King James besieged Threave Castle, which held out under James, the brother of the murdered noble. It seemed impossible to batter down the stronghold till an ingenious blacksmith, M'Kim of Mollance, constructed the enormous gun which lies to-day on the Argyle battery at Edinburgh Castle, and is known far and wide as "Mons Meg"--the "Mons" being a corruption of Mollance, whilst Meg was M'Kim's wife. He named the gun after her in ironical compliment, her voice being, he said, as the cannon's, neither soft nor low. However, this piece was dragged with enormous labour to an eminence commanding Threave Castle. The charge, it is said, consisted of a peck of powder, and a granite ball the weight of a Carsphairn cow. The Countess of Douglas, the Fair Maid of Galloway, who had married in succession the two brothers, sat at table in the banqueting hall when the gun was shot off; the ball crashing into the room, carried away her right hand, wherewith she was in the act of raising a goblet of wine to her lips. The place at once surrendered. Roofless, but still grim and massive, the castle frowns amidst the peaceful surroundings of to-day. They "still show you the gallows knob," "a large block of granite projecting from the front wall immediately over the main gateway; from here the meaner victims of the Earl's vengeance were suspended." Rarely did the knob want the ornament, of a "tassel," as, with ghastly