The mines were laid in a series of thirteen expeditions, or "excursions," as our men somewhat cheerfully called them. The ten mine-layers participated in each "excursion," all ten together laying about 5,400 mines at every trip. Each trip to the field of action was practically a duplicate of the others; a description of one will, therefore, serve for all. After days, and sometimes after weeks of preparation the squadron, usually on a dark and misty night, showing no lights or signals, would weigh anchor, slip by the rocky palisades of Moray Firth, and stealthily creep out to sea. As the ships passed through the nets and other obstructions and reached open waters, the speed increased, the gunners took their stations at their batteries, and suddenly from a dark horizon came a glow of low, rapidly moving vessels; these were the British destroyers from the Grand Fleet which had been sent to escort the expedition and protect it from submarines. The absolute silence of the whole proceeding was impressive; not one of the destroyers showed a signal or a light; not one of the mine-layers gave the slightest sign of recognition; all these details had been arranged in advance, and everything now worked with complete precision. The swishing of the water on the sides and the slow churning of the propellers were the only sounds that could possibly betray the ships to their hidden enemies. After the ships had steamed a few more miles the dawn began to break; and now a still more inspiring sight met our men. A squadron of battleships, with scout cruisers and destroyers, suddenly appeared over the horizon. This fine force likewise swept on, apparently paying not the slightest attention to our vessels. They steamed steadily southward, and in an hour or so had entirely disappeared. The observer would hardly have guessed that this squadron from Admiral Beatty's fleet at Scapa Flow had anything to do with the American and British mine-layers. Its business, however, was to establish a wall of steel and shotted guns between these forces and the German battle fleet at Kiel. At one time it was believed that the mine forces on the northern barrage would prove a tempting bait to the German dreadnoughts; and that, indeed, it might induce the enemy to risk a second general engagement on the high seas. At any rate, a fleet of converted excursion steamers, laying mines in the North Sea, could hardly be left exposed to the attacks of German raiders; our men had the satisfaction of knowing that while engaged in their engrossing if unenviable task a squadron of British or American battleships--for Admiral Rodman's forces took their regular turn in acting as a "screen" in these excursions--was standing a considerable distance to the south, prepared to make things lively for any German surface vessels which attempted to interfere with the operation.