But the wait lasted longer than Ken and Roy expected. All that day G2 cruised slowly back and forth between the big island of Marmora, where the marble quarries are, and the high coast of the European mainland, yet nothing rewarded her vigilant watch.

There was nothing to do but sit about and yarn, and more than once Roy told Ken that he wouldn't be a submarine sailor for any amount of 'hard lying' money.

It was about four in the afternoon, and Ken had been taking a quiet nap, for he had a lot of arrears of sleep to make up, when he was roused by a sudden sharp order from Lieutenant Strang.

In an instant the drowsy interior of G2 wakened into sudden life, and Ken, springing to his feet, moved forward to where Williams was standing near the forward periscope.

'What's up?' he asked in a quick undertone.

'Craft in sight. Can't tell what she is yet.'

'A warship?'

'Transport, most like, but can't say yet. Sit tight. I'll tell ye when I can see her a bit plainer.'

By the deeper hum of the engines, Ken knew that they had quickened their speed. There was a sort of suppressed eagerness about all the twenty-five men who composed the crew of the submarine. Ken longed to have a peep through the camera of the periscope, but knew it was impossible.

'She isn't much,' said Williams at last. 'Just a tramp of twelve or fourteen hundred tons. Still, she may ha' got troops aboard, and if she ain't, it's grub or munitions for them beggars in the peninsula.'