The sea was calm and the Dewey cruised on the surface, with her hatches open. The boys were able to stretch themselves in a promenade on the aft deck and found the night air invigorating as they speculated together on their mission.

They had soon to find out something of the number and character of warships in the fleet of which the Dewey was a unit. As daybreak came stealing up over the horizon they looked about them to discern many other warships all about them. Far to port, strung out in single file about a half mile apart, were three huge liners that they took to be troopships. Deployed around them were destroyers—-four of them—-riding like a protecting body guard. Bobbing about at intervals in the maritime procession were other submarines, their conning towers silhouetted against the dim skyline.

Relieved of duty, Jack and Ted went below and turned in for a two-hour sleep. When they climbed up through the forward hatch again after breakfast it was to find the sun shining bright and the fleet moving majestically eastward.

Chief Gunner's Mate Mike Mowrey confided to them that the Dewey was, indeed, bound for European waters. Lieutenant McClure had opened his sealed orders and learned that he was to report to the Vice-Admiral in the North Sea. Word had been passed around to the ship's officers and they in turn were "tipping off" their men. The Dewey was stripped for action and was to assist the destroyers in defense of the transports in the event of an attack.

The first day out was spent in drills and target practice. Late in the afternoon a huge warship was sighted dead ahead and for a time there was a bit of anxious waiting aboard the Dewey. While it was generally known that the German high seas fleet was bottled up in the Kiel Canal, there was always a chance of running into a stray raider. But very shortly the oncoming vessel broke out a flutter of flags, indicating that she was a French cruiser, and exchanged salutations with the commander of the American fleet.

The men of the Dewey soon learned that the troopships which they were escorting carried a number of regiments of marines and several detachments of U.S. Regulars bound for France. Because the submarines were slower than either the transports or the destroyers, the fleet made slow progress.

They had been at sea over a week and were entering the war zone when, late one afternoon, there came a sharp cry from the lookout in the Dewey's deck steering station.

"Periscope two points off the starboard!"

Instantly an alarm to general quarters was sounded. Jack and Ted, detailed in the same gun crew, had just come on duty at the forward gun. The Dewey's wireless was flashing the news to the rest of the fleet.

The destroyers drew in closer to the troopships and began immediately belching forth dense black clouds of smoke under forced draft that the boys divined instantly as the smoke screens used so effectively as a curtain to blind the eyes of the U-boats.

Turning her nose outward from the hidden transports the Dewey drew away in a wide sweeping circle to starboard.

"All hands below!" came the order. Immediately the deck guns were made fast and the crew scrambled down through the hatches. In a few minutes, driving ahead at full speed, the Dewey was submerged until only her periscopes showed.

All at once the crew heard a shout from the conning tower.

"There she is!" yelled Lieutenant McClure, as he stood with his eyes glued to the periscope glass.

"U-boat driving straight ahead at the smoke curtain. Port the helm!" he commanded.

The Dewey came around sharp and, in response to the guidance of her commander, began to ascend.

Having executed a flank movement, the Dewey now was endeavoring to engineer a surprise attack on the German submarine from the rear. To all intents, the German commander had not yet noted the approaching American submersible. He was going after the transports full tilt, hoping to bore through the destroyers' smoke curtain and torpedo one of the Yankee fleet.

Quickly the Dewey dived up out of the water, the hatches were thrown open and the gun crews swarmed on deck, carrying shells for their guns. Jack and Ted followed Mike Mowrey on deck and dropped into position behind "Roosey." Gazing ahead they could make out the German periscope and its foamy trail.

"Fire on that periscope," ordered Lieutenant McClure.

The U-boat was not more than nine hundred yards away, according to the Dewey's range-finder, and apparently yet unconscious of the proximity of the American submarine. In a moment the gun was loaded and ready for firing.

"Bang!" she spoke, and then every eye followed the shot. Commander McClure had jumped up on the conning tower and was hugging the periscope pole. There was a moment's silence before he spoke.

"A little short, boys," he called. "Elevate just a little more—-you've nearly got the range."

Again the gun crew leaped into action.

"Hurry, boys! he sees us now and is beginning to submerge!" yelled the young lieutenant as he followed the U-boat through his glasses.

Again "Roosey" spoke, and this time with an emphatic "crack" that boded ill for any luckless human who might get within the line of its screaming shell fire.

"O-o-o-oh, great!" cried Lieutenant McClure an instant later as he peered more intently through his glasses.

Of a sudden the periscope disappeared from the crest of the sea as though wiped out completely by the explosion of the Dewey's shell.

"No doubt of it, boys; you ripped off that periscope," announced
McClure, with an air of finality.

At their commander's words the gun crew burst into cheers. The submersible's wireless was singing out a message of good cheer to the American fleet. It was only too evident that the enemy U-boat had been crippled and put completely to rout by the daring maneuvers and deadly gunfire of the Dewey.

"Who said the Yanks couldn't stop their pesky undersea wasps?" chattered Bill Witt joyously. "If they just let us loose long enough we'll show 'em how to kill poison with poison."

Mike Mowrey was in great glee.

"Just like a grasshopper begging for mercy on a bass hook," he said jauntily, imitating with a crook of his finger the disappearing periscope.

Soon the fleet was off Cape Clear on the southernmost point of the Irish coast and very shortly headed well into the English Channel. Now every few hours the American warships were speaking one or other of the English and French patrol ships. Great was the joy of the boys aboard the Dewey when first they beheld an American destroyer out on the firing line.

"Union Jack and French tricolor look pretty good; but none of them makes a fellow's blood tingle like the Stars and Stripes; eh, chum?" queried Jack, as he surveyed an American destroyer dashing along in fine fettle. And Ted heartily agreed.

Off Falmouth, the transports, accompanied by three of the American destroyers and two English "limeys "—-as the British destroyers are known in the slang of the sea—-slipped off silently into the twilight. The American infantry and marines were to be landed "somewhere in France." Jack and Ted viewed the departure with mingled pride and regret.

"Reckon they will be in the trenches before long," ventured Ted.

"Frisking bean balls at the Fritzes," snapped Bill Witt with