laughed Dan, as he started down the steps. "I'm hoping for 'big business' this time!"

Dalzell had used the word "gig" in a figurative sense. It was a power launch that put smartly away from the "Reed" and was speedily alongside. Dan waved his hand to his chum, who was leaning over the bridge rail.

Dave did not return to the chart-room. He received the report of his chief engineer at the bridge telephone, then gazed musingly out over the crowded waters of the port. It was a busy scene, bristling with war activities.

Having compared his watch with the clock on the bridge, Dave glanced frequently at that time-keeper. Five minutes before the hour was up he gave a quiet order to the watch officer, who telephoned to the engine-room and then issued brisk deck orders. At this time Lieutenant Fernald, executive officer, joined the group on the bridge, as did also the navigation officer.

Promptly to the minute the "Grigsby," anchor up, turned and steamed slowly out of the harbor. As she passed, none of the other craft made signals. As though unnoticed Dave's ship slipped out of port, the "Reed" following.

Then out upon the Channel the two destroyers moved, into the lane now followed by all craft that sailed between England and the continent.

"All clear hereabouts," signalled the master of a small mine-sweeping craft, meaning that the destroyers, while in that immediate vicinity, might feel secure against the hidden mines with which the enemy were wont to strew these waters.

"A few miles from here," Dave murmured to Fernald, "we shall have to look after our own security. It is going to be lively work."

"Yes, sir?" Fernald inquired, with a rising inflection, for he did not know the purpose of this cruise.

Turning to make sure that the signalman could not overhear, Darrin went on, in a lower voice:

"Our orders take us out to wage war against the German mine-layers!"

"A great work, sir!" replied the executive officer with enthusiasm. "There is sure to be plenty of sport. Then the enemy mine-layers have been working more industriously of late?"

"The waters to the north are more thickly strewn with mines than at any time previously," Dave continued. "Six British mine-sweeping craft have been sent north to do all they can to remove those hidden perils from the paths of transports and freighters. Our first mission is to protect the mine-sweepers as far as possible, but we are also to keep a sharp lookout for German submarines; and especially submarines of the mine-laying kind."

"I understand, sir," Fernald nodded. The tone of enthusiasm had faded from his voice. Now he displayed only the grave interest of the professional sea-fighter.

"All officers and men will have to work twice as hard as usual," Darrin went on. "There will be some chance to sleep, but no other leisure. Meals will be taken in the least possible time. Our entire crew must be at all times ready for instant response to the call to quarters."

"That will not be hard in such times, sir," answered Fernald. "All officers and men laid in a good supply of sleep while in port. A few added waking hours in each day won't hurt any of us."

"Direct all officers to see that they and their men are fully awake and alert at all times when they are on duty," continued Dave. "Otherwise, we are not likely to make port again. Dalzell and I have been intrusted with keeping down the mine-laying peril as close to zero as possible."

"Very good, sir," replied Lieutenant Fernald. That capable executive officer had nothing more to say at present, for his quick mind was already devising methods for keeping the crew unusually alert.

An hour and a half after sailing night had settled down. The English shore was but a vague, distant line. A short, choppy sea was running. In the sky was a new moon that would set early.

The watch had changed, but Dave and his executive officer remained on the bridge. Down in the wardroom such officers as were off duty were stowing away food in record time.

Half a mile off to the west steamed the "Reed." Suddenly the lookouts on both craft reported a vessel ahead. Orders quietly given sent the men to gun stations. All eyes were turned on the approaching craft. Then her identification signal shone forth in the night. The stranger was a British scout cruiser racing back to port from some errand.

In almost the same instant Dave and Dan displayed recognition signals, yet the two Yankee craft closely watched the stranger until she moved between them, when she was fully recognized as one of John Bull's friendly sea-racers.

"Any enemy signs?" Dave signalled.

"No," came the answer.

Soon the British scout cruiser had passed on into the night and vanished, but the Yankee lookouts kept vigil even more zealously than before.

Half an hour later an English patrol boat, after exchange of signals, passed near by on Dave's port side. Twenty minutes after that two British mine-sweepers were found at work combing the seas with their wire sweepers. If those wires should touch a hidden mine it would be quickly known to the seamen who operated the mine-detecting device, and the mine would be hauled up and taken aboard the mine-sweeping craft, provided it did not explode in the meantime.

As these two mine-sweepers were under Darrin's command, at need, he steamed near one of the pair, and, ordering a navy launch over the side, went to visit one of the Britons.

"There's not very much in the way of catches to-night, sir," reported the commander of the sweeper, a ruddy-faced, square-shouldered young Englishman in his twenties, who had been watch officer on a steamship at the outbreak of the war. "Sometimes the fishing is much better."

"This is the area in which we have been ordered to make a strict search," Dave observed.

"I know, sir. But, according to my experience, we may search for hours and find nothing at all, and then, of a sudden, run into a mine field and take up a score of the pests."

"What is your present course?"

The commander of the mine-sweeper named it, adding the distance he had been ordered to go.

"And the other sweeper sticks near by you?"

"Yes, sir. In that way there's a much better chance of one of us striking a regular mine field. Then again, sir, if one of us gets into trouble, as sometimes happens, the other craft can stand by promptly."

"What is the most common trouble?"

"First," explained the Englishman, "being torpedoed by a submarine; second, touching off a mine by bad handling; third, being sunk by some raiding German destroyer."

"Then you often hit mines?"

"Since the war began, sir," replied the young Englishman, "we've lost—" He named the number of mine-sweepers that had disappeared without leaving a trace, and the number that were definitely known to have been torpedoed or to have hit floating mines.

"As you see, sir," the Englishman went on, "it's no simple thing that we have to do. I lay it to sheer luck that I've escaped so long, but my turn may come at any moment. I've lost a number of friends in this same branch of the service, sir."

"Then you would call mine-sweeping the most dangerous kind of naval service performed to-day?" Dave suggested.

"I don't know that I'd say that, sir, but it's dangerous enough."

Many more pointers did Darrin pick up from this young officer of long experience in mine-hunting.

"I'm going farther north," said Dave. "If you run into anything and need help, send up rocket signals and we'll steam back to you at top speed."

Before ten o'clock that night Darrin had encountered and spoken with or signalled to the