ON the 26th of July, 1864, a magnificent yacht was steaming along the North Channel at full speed, with a strong breeze blowing from the N. E. The Union Jack was flying at the mizzen-mast, and a blue standard bearing the initials E. G., embroidered in gold, and surmounted by a ducal coronet, floated from the topgallant head of the main-mast. The name of the yacht was the DUNCAN, and the owner was Lord Glenarvan, one of the sixteen Scotch peers who sit in the Upper House, and the most distinguished member of the Royal Thames Yacht Club, so famous throughout the United Kingdom. Lord Edward Glenarvan was on board with his young wife, Lady Helena, and one of his cousins, Major McNabbs. The DUNCAN was newly built, and had been making a trial trip a few miles outside the Firth of Clyde. She was returning to Glasgow, and the Isle of Arran already loomed in the distance, when the sailor on watch caught sight of an enormous fish sporting in the wake of the ship. Lord Edward, who was immediately apprised of the fact, came up on the poop a few minutes after with his cousin, and asked John Mangles, the captain, what sort of an animal he thought it was. "Well, since your Lordship asks my opinion," said Mangles, "I think it is a shark, and a fine large one too." "A shark on these shores!" "There is nothing at all improbable in that," returned the captain. "This fish belongs to a species that is found in all latitudes and in all seas. It is the 'balance-fish, ' or hammer-headed shark, if I am not much mistaken. But if your Lordship has no objections, and it would give the smallest pleasure to Lady Helena to see a novelty in the way of fishing, we'll soon haul up the monster and find out what it really is." "What do you say, McNabbs? Shall we try to catch it?" asked Lord Glenarvan. "If you like; it's all one to me," was his cousin's cool reply. "The more of those terrible creatures that are killed the better, at all events," said John Mangles, "so let's seize the chance, and it will not only give us a little diversion, but be doing a good action." "Very well, set to work, then," said Glenarvan