Their praise seemed to please Gill, for he proceeded to cut some gigantic sandwiches out of stale bread and excellent cold boiled pork, and to these also the hungry youngsters did justice.

‘What ship is this?’ asked Ken, when the first pangs of hunger had been satisfied.

‘"Maid o’ Sker.”  Mine—­sweeper.  Skipper, Seth Grimball,’ was the brief answer.  Then, after a pause, ‘Where did you blokes come from?’

Ken told him, or rather began to, for before he had finished, the steady beat of the engines suddenly slackened.

‘Cotched one, I reckon,’ remarked Gill briefly, and hurried on deck followed by the two boys.

The ‘Maid of Sker’ was the ordinary type of North Sea trawler, and so far as Ken and Roy could see, her fellow, whose name Gill told them was the ‘Swan of Avon,’ was her double.  They were moving exactly parallel, at a distance of about a cable (220 yards) apart.  Between them towed a thin steel hawser set to a depth just sufficient to catch the mooring cables of the mines which were plentifully strewn in the channel.

‘Caught one, you say?’ whispered Ken in Gill’s ear.  ‘A mine, you mean?’

‘Ay.  Look at the cable.  She’s foul of it all right.’

Certainly the cable was sagging in a curious fashion.

‘What do you do with them?’ asked Roy.

But Gill had already run aft to assist.  Low-voiced orders were heard, and the ‘Maid of Sker’ began to forge slowly ahead.

‘I think they’re going to tow it out of the channel,’ Ken said to Roy.  ‘That’s what I believe they do.’

’But I thought the beastly things exploded when you touched ’em,’ said Roy.

’Some do.  That’s the sort with steel whiskers on them.  The others are what they call tilting mines.  They blow up when their balance is upset.’

‘And which is this?’

’I don’t know any more than you, and I don’t suppose the skipper does, either.  All these mines swim some way under the surface.’

‘What’s the betting on her going off?’ said the irrepressible Roy.

‘She won’t,’ said Ken confidently.  ’These chaps know how to handle her.  She—­’

He stopped short, and involuntarily flung up his hands before his eyes.  A cone of blinding white light had sprouted suddenly from the Asiatic shore, and in its cold brilliance the outlines of the two trawlers, the people on their decks, the cable towing between them, and a wide patch of rippling water stood out as clearly as in the broadest daylight.  It was a searchlight from Kephez Point at the southern angle of Sari Siglar Bay.

‘Haul up there.  Haul on that cable.  Sharp now!’ bellowed Captain Grimball, and his men sprang to obey.  He himself dashed into the little deckhouse and was out again in an instant with a rifle in his hand.

In the dazzling glare a great bulbous mass of dark-coloured metal heaved slowly up out of the water midway between the two trawlers.  It was hardly in sight before Grimball had flung his rifle to his shoulder and fired.