‘What’s the matter?  They haven’t begun to fire yet,’ said Roy quickly, as he thrust a third shell into the open breech.

[Illustration:  ‘Up shot a sheet of crimson flame.’]

‘So much the better for us,’ Ken answered.  ’Mr Dimmock, this one ought to do for the nearest barge.’

Hastily Dimmock sighted again at the blunt, low-lying object which loomed dimly ahead in the wet darkness.

Once more the smart little gun spoke, but the crack of the report had hardly sounded before it was drowned by the most appalling crash.  Up from the stricken barge shot a sheet of crimson flame, a blaze of fire which mounted a hundred feet into the murky air, and in spite of fog and mist flung its glare upon the iron cliffs on either side the narrow straits.

The launch shuddered as though she had struck a reef, and the blast from the explosion flung every soul who was standing up flat upon her decks.

Hard upon the roar came a wave, a wave which rose high over the bows of the long, slim craft, and swept across her in a torrent of cold, salt water.

It washed Ken back against the rail, which he clutched at desperately, and so saved himself from going overboard.

Dazed and confused, he struggled to his feet.

‘Roy!’ he cried thickly, ‘Roy!’

‘All right.  We’re all right,’ came a hoarse reply, and Roy’s tall figure rose from close under the opposite rail, and grasping Dimmock, lugged him to his feet.

‘Gad, that’s done the trick!’ he panted.  ’The other barges are gone.  So’s the tug.  We’ve bust the whole caboodle.’

From aft came Captain Carrington’s voice, shouting for ‘Full speed ahead!’

Time, too, for the gunners in the forts, recovering from their paralysed amazement, were already getting busy and the roar of great guns was followed by the rocket-like hiss of shells.

Like a frightened hare the launch gathered speed and darted away downstream.  Shells, each big enough to smash her to kindling, fell on every side, but the gunners on both sides were firing too high, and by a series of miracles the launch was not touched.

Searchlights sprang out, their white fingers feeling through the murk.  But no searchlight ever made will penetrate a thousand yards of fog, and the dull glares only served to warn the steersman of the launch of dangers to be avoided.

‘Jove, we’ll do it yet, Ken,’ cried Roy, shouting so as to be heard above the thunderous din of the guns.

‘It will be a miracle if we do,’ Ken answered.  ’Remember we have to run the gauntlet all the way down.’

‘It doesn’t follow,’ Roy said quickly.  ’They haven’t seen us, and they’ll take it for granted that it must have been a submarine.  Why, even the sweepers haven’t ventured up here.’

‘I only hope you’re right,’ replied Ken fervently.

‘Ah!’ he broke off, as a shell whizzed over so near they felt the wind of it.  ‘That was close.’