'Oh yes, the shark is one of our oldest inhabitants.'
We talked a little more and then I dropped it. They had a lot to learn yet and it came best in small doses. And there was plenty of time for talk on this voyage. We headed south-south-west to cut through the Bahamas and the approach to the Windward Passage. Once in the Passage we kept as clear as possible of Cuba – once we came across an American destroyer on patrol, which did us the courtesy of dipping her flag, to which we reciprocated. Then there was the long leg across the Caribbean to Colon and the entrance to the Panama Canal.
By then we had done our testing. There were minor problems, no more than teething troubles, and generally I was happy with the way things were going. Stopping to dredge a little, trying out the winch and working out on- station routines, was an interesting change from what we had been doing and everyone enjoyed it, and we remained lucky with the weather. I got some nodules up but there was a lot of other material, enough to cloud the issue for everyone but Geordie. Among the debris of ooze, red clay and deposits we found enough shark's teeth and whale's earbone to give everyone on board a handful of souvenirs.
Both Geordie and Bill were becoming more and more interested in the nodules and wanted to know more about them, so I arranged for another lab. session with them one day. I'd been assaying, partly to keep my hand in and partly to check on the readiness of my equipment for the real thing.
'How did the Atlantic nodules turn out?' Geordie asked. On the whole he did the talking – Bill watched, listened and absorbed.
'Same old low quality stuff that's always pulled out in the Atlantic,' I said. 'Low manganese, low iron and hardly anything else except contaminants, clay and suchlike. That's the trouble in the Atlantic; there's too much sediment even on the Blake Plateau.'
'Why does manganese behave this way – why does it lump together?'
I laughed. 'You want me to give you a course of physical chemistry right now? All right, I'll explain it as simply as I can. Do you know what a colloid is?'
Two headshakes.
'Look. If you put a teaspoon of sugar into water you get a sugar solution – that is, the sugar breaks down right to the molecular level and mixes intimately with the water. In other words, it dissolves. Right?'
'Right.'
'Now what if you have a substance that won't dissolve in water but is divided into very fine particles, much smaller than can be seen in a regular microscope, and each particle is floating in the water? That's a colloid. I could whip you up a colloid which looks like a clear liquid, but it would be full of very small particles.'
'I see the difference,' Geordie said.
'All right. Now, for reasons that I won't go into now, all colloidal particles must carry an electric charge. These charges make the colloidal particles of manganese dioxide clump together in larger and larger units. They also tend to be attracted to any electrically conductive surfaces such as a shark's tooth or a bit of clay. Hence the nodules.'
'You mean,' said Bill slowly, 'that having broken down a long time before, the manganese is trying to get together again?'
'Pretty well just that, yes.'
'Where does the manganese come from in the first place -when it starts clumping, that is?'
'From the rivers, from underground volcanic fissures, from the rocks of the sea bottom. Fellows, the sea out there is a big chemical broth. In certain localized conditions the sea becomes alkaline and the manganese in the rocks leaches out and dissolves in the water… .'
'You said it doesn't dissolve.'
'Pure metallic manganese will dissolve as long as the conditions are right, and that's what chemists call a 'reducing atmosphere'. Just believe me, Geordie. Currents carry the dissolved manganese into 'oxidising atmospheres' where the water is more acid. The manganese combines with oxygen to form manganese dioxide which is insoluble and so forms a colloid – and then the process goes on as I've described.'
He thought about that. 'What about the copper and nickel and cobalt and stuff that's in the nodules?'
'How does the milk get into the coconut?'
We all laughed, taking some of the schoolroom air out of the lab. 'Well, all these metals have certain affinities for each other. If you look at the table of elements you'll find they're grouped closely together by weight – from manganese, number twenty-five, to copper, number twenty-nine. What happens is that as the colloidal particles grow bigger they scavenge the other metals – entrap them. Of course, this is happening over a pretty long period of time.'
'Say a hundred million years or so,' said Geordie ironically.
'Ah well, that's the orthodox view.'
'You think it can happen faster than that?'
'I think it could happen fast,' 1 said slowly. 'Given the right conditions, though just what these conditions would be I'm not sure. Someone else doing research thought so too, though I haven't been able to follow his reasoning. And I have seen peculiarities that indicate rapid growth. Anyway that's one of the objects of this trip – to find out.'
What I didn't say in Bill's hearing was that the 'somebody' was Mark, nor that the peculiarities I had seen were contained in the prize nodule left from his collection. And there was something else I didn't talk about; the peculiarities that led to high-cobalt assay. I was beginning to grope towards a theory of nodule formation which, though still vague, might ease the way ahead. I was becoming anxious to know how Campbell's cipher expert had made out in translating Mark's diary.* 3*
Ten days after leaving the Blake Plateau we warped into the dockside at Panama. At last we were in the Pacific, all my goals a step nearer. Campbell was waiting for us, jumped spryly aboard and shook hands with me and Geordie, waving genially at the rest of the crew.
'You made a good fast trip,' he said.
'Not so bad,' said Geordie complacently.
Campbell looked about the Esmerelda and at the crew who were busy stowing sail and clearing the decks. 'So this is your crew of cut-throats and desperadoes,' he said. He was in a jocular mood- a mercurial man. 'I hope we won't need them.' He took my arm and walked me along the dock, amused at my wobbling land-legs.
'I've booked you into my hotel for a night or so; there's no reason why you shouldn't have a last taste of luxury before the big job. Geordie too, if he wants it. I'll expect you both to dinner – you can't miss the hotel, it's the Colombo, right on the main street. You can tell me all about the trip then. Meantime I want to talk to you in private, now.' He steered me into one of the waterfront bars that always seem to be handy, and I sat down thankfully in front of a large glass of cold beer.
Campbell wasted no time. He produced a biggish envelope from his jacket. 'I had photostats made of the diary pages,' he said. The original's in a bank vault in Montreal. You don't mind? You'll get it back one day.'
'Not at all,' I said.
He shook out the contents of the envelope. 'I got the translation done. My guy said it was a bastard of a job – he only hopes he's got the scientific bits right.'
'We'll soon find out.' I was stiff with eagerness.
Campbell handed me a neatly bound booklet which I flicked through. 'That's the stat of the original diary. This one's the translation. There are reproductions of all the drawings at the back. The whole thing looks screwy to me – it had better make sense to you or this whole thing is a bust already.' His good humour had already evaporated, but I was getting used to his changes of mood.
I glanced through it all. 'This is going to be a long job,' I said. 'I'm not going to be able to make any snap judgements here and now; I'll look at this lot this afternoon, in the hotel room. Right now I want to go back to Esmerelda and sort out procedures with Geordie, pack my gear and go and take a shower and a clean-up.'
If he was disappointed he didn't show it – clearly what I said made sense. And so it was not until I was lying, damp and half-naked in the blessedly cool hotel room a couple of hours later that I finally opened the envelope. The translation of the cipher was pretty well complete except for a few gaps here and there, but it didn't improve matters as much as I'd hoped. The thing was disappointingly written in a kind of telegraphese which didn't make for easy reading. It was a true diary and evidently covered the last few months of Mark's life, from about the time he left the IGY, although there were few dates and no place names written in clear at all.
I wondered if he'd always kept such a diary, and decided that he must have done so – diary-keeping is a habit
