'I thought it was the squall to end all squalls,' I remarked thoughtfully. The salt had started to blur the sheen of Shelborne's sealskin reefer jacket. The weather seemed to be working up.
'I'm glad the wind wasn't hard for my birds,' he replied. 'A gale could blow us clean away, standing up here. The water comes so high sometimes that we find fish, big ones, right here up among the rocks.'
Minnaar was restive. I, too, was anxious for the ship.
'Where is the best holding-ground in the bay?' I asked.
He was a long time in replying, but when he did, it was as if he had come to some conclusion, for his voice was decisive and his eyes alive to the scene about us.
'I think I'll assign you to the lee of Hottentot Reef.'
There were curious overtones in his voice. At the time I put it down to his preoccupation with the birds.
'Where the hell is that?' asked Minnaar. I, too, did not remember Hottentot Reef on the charts, but to trust them was as chancy as Russian roulette.
'It's about three cable-lengths to the nor'-nor'-east of where you are now. You should get some protection there, and you'll also benefit by the lee of Mercury.'
I laughed nervously. 'At the whisper of a rising sea, you can count on a high-tailing start from me.'
Shelborne said, 'It never does to write off the sea. Rhennin should remember that.'
Was it a statement of fact or was there a concealed threat in the calm, resonant voice?
I went right on, not caring about his reaction earlier about the Glory Hole. 'Where is the entrance to the Glory Hole?'
Relaxed, he pointed beyond the seal colony; he might have been a tourist courier at a beauty spot. To me it looked exactly like any other part of the rock-bound shore.
'I'd like to have a closer look,' I said.
'Not without ropes,' he warned. 'One slip and you'd be into the sea.'
'I'll use a boat then — soon, maybe.'
'Take my flatboom, rather — it's built for these seas.'
I was puzzled about Shelborne's sudden change of attitude. I knew how bitter he was about losing the concession and yet he was being helpful — helpful enough almost to have justified something of Rhennin's Ј10,000 — even to offering his own boat.
The encompassing arms of the bay were opaque behind a veil of spray. An ordinary wave smashes on to rocks with a force of 4000 lb. to the square foot; this sea was the Joe Louis of them all. From the deep ocean the waves — kicking, squirming, trying to break free of the wind's grip — were marched towards Mercury by the south-wester and pitched mercilessly at the rocks. The stricken water burst into a thousand fragments and was scattered as spray high up the slopes, almost up to where we were standing. A great single burst of shattered sea catapulted from the shore for fully a hundred feet upwind.
'Good God!' I exclaimed.
Shelborne smiled. 'The Glory Hole. Compressed air.' The heavy thud came to our ears, like a distant shell-burst. 'You see, the waves compress into the Glory Hole. There comes a point of no return. The air literally explodes under the pressure. It throws the water back even against the power of the wind, as you see.' He voiced my own anxieties. 'You'll have fun in the Mazy Zed in a sea like this.'
I wasn't going to let him know what I was thinking, however. 'You saw the model. The low freeboard and absence of gunnels will cope with it.'
Shelborne nodded towards the two wrecks at the base of Sudhuk. 'They also knew how to cope. When do you start your survey?'
'Tomorrow.'
'If Mercury permits, you mean.'
I deliberately faced away from him. He seemed to have an uncanny knack of being one jump ahead. There was a rough incline on the right. On it were a number of shaped oblongs, all the same size. For a moment I paused, trying to make out what they were. Then I shuddered. The scores of sinister chevrons, covered in a patina of unscraped guano, were the coffins of the unquiet dead of Mercury, cemented to the rock face. A rough little hut, which presumably contained the implements for the final committal of these sleepless ones, stood against a low wall. The coffins were whiter than the corpses inside; the hut, too, was whitewashed in guano.
Shelborne followed my glance. 'It is the one place on the island I don't allow guano to be scraped. I can't keep the birds out — after all, they were here first.' I could see them settling down among the coffins. 'I put up a wall to keep out the seals, but the birds found a use for it. Look!'
A gannet spread his six-foot wingspan and ran along the wall, mimicking a carrier take-off.
'Come,' said Shelborne.
Driven by a sort of compulsive horror, Minnaar and I followed him to the cemetery. We climbed into it over a rough stile bridging the wall. Gannets barred our path. A small colony of penguins, fighting a rearguard action against extermination by the birds, held on to a corner of the graveyard. The birds struck at Shelborne's ankles, but he side-stepped adroitly. I kicked out involuntarily when a vicious beak dug into me. In a moment, a dozen more powder-blue beaks and yellow heads were arcing at me. I swore and kicked them aside. My sea-boot dug into the guano. Something small and bright was dislodged. I picked it up.
It was a German Knight's Cross, with Swords and Diamonds.
The tiny lettering engraved on it stifled my call to the other two ahead. I thrust it quickly into my pocket.
It read: 'Korvettenkapitan Dieter Rhennin. U-68. May 1942.'
7
'Make the control switch!'
From my vantage-point on the summit of Sudhuk, the Praying Mantis in the bay half a mile away looked farther than she actually was; however, the electronic instrument I was testing told me it was no more than that. I glanced along the line of sight and gave my orders into the two-way radio telephone. The ship was anchored in the lee of the serrated rocks Shelborne had called Hottentot's Reef. The Hydrodist, as the instrument was called, calculates the travel time of radio waves between two points and is wonderfully accurate — it has an error of only about three parts in a million. A South African invention, it was first used for land surveying and then adapted to marine work with outstanding time-and-effort saving results.
Minnaar's flat-vowelled voice came back from the master instrument aboard the old whaler: 'Standing by to calibrate A-pattern phase.'
It had not taken him long to grasp the principles of the instrument and I felt elated as I stood on top of Sudhuk knowing that soon I would have on paper a picture of Mercury and its surrounding sea-bed. The Hydrodist, on a wooden tripod the height of a man, looked like a portable public telephone, except that in front was set a metal dish the size of a soup plate in which was placed a cathode tube. Below the tube itself, on the face of the reflecting dish, were calibration scales like saddle-stitching in metal.
I fiddled with the cavity tune control on the left of the control panel. 'A-pattern test,' I said into the built-in radio telephone. 'Standard megacycle frequency — how are you receiving?'
'Fine, man, okay,' replied Mannaar from the ship. 'No stray reflections in the microwave beam.'
'What about ground reflections?'
'Negligible, negligible,' he said. 'That's a fine spot for a slave station you've got up there on Sudhuk, Skipper.'
'Plenty of wind,' I replied.
'Christ!' He laughed. 'Wish I had it down here! How these bladdy birds stink!'
I had decided to establish two 'slave stations' — the necessary shore adjunct to the master instrument aboard the Praying Mantis — one of them on top of the towering cliff, from where I was now carrying out a series of calibration tests between the Hydrodist and the ship. The other 'slave station' was to be at the northern end of the bay. It takes a day or two to calibrate the master instrument and after that surveying goes ahead. My modern electronic method made the laborious old coastal triangulation system, using large numbers of floating beacons as well as land points, as out of date as a piston-engined aircraft. My system enabled a continuous and accurate plot to be made in about one-twentieth of the time taken by old methods and, unless atmospheric conditions were particularly bad, surveying could go on day and night, if necessary in darkness, mist, rain or fog, the latter being a big consideration on the Sperrgebiet where overnight fogs do not usually lift until the middle of the morning.