The results were dotted around my first one like Campbell's bullet-holes around mine on the target. 4.38 – 4.29 – four times I tested, and every test checked out.

I croaked, 'Hell, I've got to tell Geordie. He's got to change course.'

I dashed up on deck leaving the girls thumping each others' shoulders. Ian was at the wheel. 'Whoa up!' I shouted. 'We're going back to the last site.'

His eyes widened. 'You've never found something?'

'That I have! Where's Geordie?'

'He's off watch – I think in his cabin.'

I left him to supervise the change of direction and pounded below. But Geordie wasn't impressed. 'Four per cent is a long way from ten,' he said.

'You damn fool, Geordie. It's twice the percentage that's been found in any nodule before, apart from the one we had in London. We must have struck the edge of the concentration.'

'Well – what now?'

'We go back and cruise that area, keeping an eye on the echo sounder. That'll probably tell us something.'

He swung out of his bunk and put his trousers on. 'It might tell you something; it won't mean a thing to me. Thank God we've been keeping careful records of our position.'

'Come on – let's tell the boss.'

Campbell had already been told. We found him in the lab with the girls, looking at the figures. He turned as we came in, his eyes bright with expectation. 'Have we found it, Mike?'

I was suddenly cautious. I said carefully. 'We've found something. Whether it's what we hope is another thing.'

'You goddam scientists,' he grumbled. 'Why can't you ever tell a straight story?'

I pulled out the chart I had been making from the recording echometer. 'There's a ridge running along here, roughly north and south,' I said. The top is within nine thousand feet of the surface. We picked up our prize nodule here, on the east side of the ridge at eleven thousand feet. I'd like to sail at right angles to the ridge, striking east- this way. I'd like to see how the depth of water goes.'

'You think the depth might have something to do with this?'

'It might. It would be the natural accumulation area for the greatest volume of nodules hereabouts, rather than in the very shallowest areas – even though there's never more than one layer of thickness of nodules anywhere.'

'I thought they'd be there in great piles, humped up together.'

'Sorry, no,' I said. 'That's never been found. The best evidence from some deep-sea photographs is that there are parts of the sea-bed which are lumpy underneath the sediment layer, indicating that many more nodules might be buried there, but in that case they'd have stopped growing anyway, being cut off from their life-line – the sea water itself.'

But for the only time they were not interested in my impromptu lecture. I hastened to correct myself.

'Don't worry, the billions of tons I promised you will be there, even if it does lie only one layer thick. There are lots of things we have to find out still.'

We arrived in the vicinity of the last site with members of the crew, rather ludicrously, peering at the surface of the ocean as if it could show them anything. Geordie said, 'Right – now which way?'

I drew a pencil line on his chart. 'Follow that course, please.'

As we sailed I watched the trace of the echometer with intense concentration. The line showed a gradual deepening of the water – not a sudden drop, but a falling away as though from mountains into the plains. After we had gone about ten miles the bottom began to come up again from 13,000 feet. I made sure it wasn't just a local condition and then said, 'I want to go back about two miles.'

'Okay,' Geordie said, and gave brisk orders. We were doing most of this work under engine as it was tricky for sail, and I was grateful for the continuing calm weather which gave us the minimum of wind and ocean drift to contend with. I thought for just one envious moment of how easy it would all be on land.

Campbell looked at my tracing. 'What do you think?'

There's some sort of valley down there,' I said. 'We've come from a ridge, crossed the valley and begun to climb up towards the opposite ridge. I want to go back and dredge where it's deepest – it's about 13,000 feet.'

Campbell rubbed his cheek. 'Bit deep for commercial dredging with a drag line. You waste too much time just going down and coming up again.'

'If the stuff's rich enough it should pay.'

He grunted. That's what we're here to find out.'

By now everyone knew what was in the wind and there was a lot of tension as the dredge went down. Ian was at the winch and Geordie himself at the wheel, keeping Esmerelda on station. It seemed a particularly long time before Ian, watching the cable tension meter, slipped the winch out of gear and said, 'She's bottomed.'

Geordie's hand went to the engine controls. Campbell swung round, fussing like an old hen. 'Careful, Geordie, we don't want any mistakes now.'

Esmerelda crept forward, taking the strain on the cable. I could visualize the dredge at the bottom of the abyss, scraping forward in utter darkness, gathering the nodules and debris into its maw like a vast-jawed prehistoric creature.

Then the job was done and Ian had the winch in gear again. The drum started to turn and the crew began to stow the wet and slimy cable into the hold as it came off the drum. Again it seemed to take ages and the tension increased until our nerves fairly twanged. Taffy said hoarsely, 'For God's sake, Ian, pull your finger out!'

Geordie said calmly, 'None of that, now. Take it easy, Ian -you're doing just fine.'

Thirteen thousand feet is nearly two and a half miles. It takes a long time to haul a full dredge up from that depth, especially when you're not too sure of your cable and taking it slowly. Normally nobody took any notice until the bucket came inboard, but this time everyone's attention was riveted, and when at last the dredge broke surface there were many willing hands to swing the boarding derrick out and bring the haul in.

Geordie had handed over the wheel to Danny and he ran forward to help release the load. A cascade of nodules swept onto the deck, together with the usual lot of slimy mud. Taffy stooped and picked up a nodule. 'This doesn't look any different to me,' he said, clowning disappointment.

Ian said, 'Ye daft loon. Leave it to Mike, would you? He knows what he's doing.'

I hoped he was right.

Campbell said, 'How long, Mike?'

The usual three hours. I can't do it any faster.'

Nor did I – in fact it took longer. The lab wasn't very big and we had enough trouble with three of us working there. Now Campbell insisted on coming in and watching, and wherever he stood or sat he was in the way. In the end I bundled him out despite his protests, but I could hear him pacing up and down in the passage-way.

At the end of three and three-quarter hours I opened the door and said, 'Congratulations, Mr Campbell. You've just become the father of a 9.7 per cent cobalt nodule.'

His eyes lit up. 'We've hit it! By God, we've hit it!'

'Bang on the nose,' I agreed happily.

He leaned against the bulkhead and sighed deeply. 'I never thought we'd make it.' After a few moments his brain started to function again and he said, 'What's the density?'

Ten pounds to the square foot. That'll keep you busy for the next few years.'

His smile grew jubilant.

'Come up to the saloon, all of you. Let's have a drink on it. Get Geordie down here.'

In the saloon he opened the liquor cabinet and produced bottles of whisky and gin, and set about pouring drinks with great energy. Clare and I managed to linger in the passage just long enough for a quick hug and kiss before joining him with Paula, and Geordie arrived a moment later, beaming.

To you, Mike. You've done a great job,' Campbell said expansively.