Now, gentlemen, you know as much as I do about the business. We must find the Impregnable, take possession of her—by force, if necessary—and bring her back to port pending Admiralty investigation. All ready, Mr. Spanner?" he added, addressing the engineer-lieutenant.

"All ready, sir," repeated Spanner. "The whole of the petrol-tanks are filled."

The officers went on deck. Men were busily engaged in easing off the steel hawsers by which the destroyer was secured to the jetty. The signal for "permission to part company" was fluttering from her mast. head. Aft the awnings had been unrigged, and were being handed down for stowage below.

Presently a hoist of signal flags was run up to the yard-arm of the semaphore tower.

"Permission, sir," reported the signalman of the destroyer, laconically.

The engine-room telegraph bell clanged, the water churned under the destroyer's stern as her propellers began to revolve. The last "spring" that held her to the shore was cast off, and the Frome started on her mission of investigation.

Three hours later she was off Beachy Head, but, although keeping in touch with Portsmouth Dockyard by means of wireless, and communicating with every vessel that passed up and down that busy highway—the English Channel—the Impregnable seemed to have vanished, leaving no trace behind her.

"Wreckage, sir," reported the look-out.

Heading towards the spot, and ordering the propellers to be stopped, Drake got his glasses to bear upon the spot. There were a number of oars, some gratings, a large hatch, and a yellow-painted lifebuoy, bearing the name "Hekla, Rotterdam."

"That's the name of one of the tugs, sir," said Fielding. "So the master of the Wontwash has not been telling a mere fairy tale."

"That's so," assented the lieutenant-commander. "I suppose we ought to secure that lifebuoy as evidence. Stand by with a boathook there."

Slowly the Frome forged ahead, but with little way on she was scarcely under control. The lifebuoy was passed ten yards to leeward.

"Be careful of the propellers, sir," cautioned Fielding. "There's a lot of wreckage about. Shall we pipe away the collapsible?"

Drake assented, but as Cardyke went aft to take charge of the Berthon one of the starboard propellers became entangled in a length of floating grass-rope. In a second the fibre was wound round the tail shafting as hard as a steel band.

"Hang it!" muttered Drake. "That's done it. I wish to goodness I'd sent away the boat instead of drifting into the middle of this stuff."

In four minutes the Berthon was slung outboard by means of the quadrant davits, and her crew rowed towards the derelict lifebuoy.

"Here you are, sir," said the bow-man to Cardyke, as he dexterously whisked the salvaged object into the boat. "There's some scrawl on it."

Scored deeply into the canvas were some words written in pencil. The midshipman examined the writing, but it was beyond him to decipher its meaning. It was in Dutch, a language that Cardyke was not familiar with, although it bore a slight resemblance to German.

On returning to the Frome the mid. produced his prize; but his superior was too intent upon the damage to the propeller to take very much notice of it. Nor was it till Cardyke pointed out that there was writing upon the buoy that Drake gave his attention to it.

"We've some good evidence here, by Jove!" exclaimed Drake. "Now comes the task of running down the miscreants."

"But the propeller?"

"Let it rip. We'll run her on three."

"That ought to give her twenty-three knots at the very least, sir," suggested Spanner, who had come up from the engine-room to report.

"Not with the helm slightly over to counteract the unequal drive," observed Drake. "She'll do seventeen comfortably, and I doubt whether the Impregnable in tow will be making more than seven. I'll carry on, even if there's only one propeller left."

Communicating his find by wireless Drake received instructions to cruise eastward, in order to effect a junction with two destroyers sent out from Dover, unless she picked up definite information from passing vessels that might enable her to follow in the track of the filibustered battle-cruiser.

"It won't do to fall in with the Dover t.b.d.'s," remarked Fielding. "They'll know we are crippled, and our chances of gaining kudos will be knocked on the head."

"I don't mean to if I can avoid it," agreed Drake. "We'll shape a course S.S.E. for a couple of hours, and then N.N.E. for another two hours, and so on. We'll still be carrying out instructions, you see, but it will be a precious long time before we get in touch with the Dover destroyers."

Fielding and Cardyke smiled. They knew Drake well enough by now to know that if there were a way of gaining his end he would generally do it successfully and diplomatically.

"It's my private opinion," continued the lieutenant, "that the Impregnable is not heading up-Channel at all, but rather towards the Atlantic. I don't know why, but that's my firm conviction; so the longer we take before we hear any news the sooner we'll be able to retrace our course. I only hope that the other destroyers sent from Portsmouth and Portland won't snap her up."

"So do I, sir," agreed Fielding.

"Sail-ho, on the starboard bow," sung out the look-out man.

"A tramp, judging by the smoke," remarked the sub. after the lapse of a few minutes.

Soon the vessel was observed to be steaming eastwards, so slowly that the following wind drove her smoke in a dense, trailing cloud over her bows.

Directly the Frome was within signalling distance the tramp made her number.

"SS. Steephill Castle of Hull," announced Fielding, after consulting the register. "She's light, by George! One blade of her propeller is quite clear of the water."

"Yes; I shouldn't care to be caught out in dirty weather in a craft so high in ballast as that," added Drake. "We'll close, and ask her if she has any information to give."

Drake made known his request by megaphone, and in reply the master of the tramp shouted from the bridge—

"Cruiser, two masts and three funnels, in tow. Passed her three and a half hours ago. Thought she had broken down."

"On what course?" asked Drake, eagerly.

"Due west, I should think, sir," replied the "old man." "Anything amiss?"

"We hardly know till we find her," replied the lieutenant, guardedly.

The Steephill Castle dipped her ensign in farewell, and the Frome returned the compliment; then, describing a quarter-circle, the destroyer headed due west on her quest for the filibustered Impregnable.

CHAPTER IV

THE OUTRAGE ON THE HIGH SEAS

It will now be necessary to follow up the events relating to the object of the torpedo-boat destroyer Frome's search.

The scrapped Dreadnought-cruiser Impregnable had been sold by public auction, the purchaser being Mynheer Van der Coote, shipbreaker, of Rotterdam. According to the usual terms of sale the purchaser was bound to complete the breaking-up of the ship within six months. The machinery could be utilised again, and, in consequence, was in fair order. Owing to the fact that it would be necessary to employ a large engine-room and stokehold staff to take the ship across to Holland under her own steam, Mynheer Van der Coote took the far more economical course of sending two powerful tugs to Portsmouth to tow the Impregnable to her last port.

Directly the cruiser gained Spithead the two dockyard tugs cast off and returned. The last link with Great Britain had been severed; the purchase money had been paid,