The boats are daubed-one can hardly call it painted-in bright, garish colours of yellow, blue and white. It is for a purely functional purpose, to waterproof the canvas, and they splash on whatever paint they can find, or beg from the occasional ship. The boats are the finest sea-going craft in the world. I would go anywhere with a crew of ten Tristan boatmen and a Tristan whaleboat. The boatmen have been apprenticed the hard way by the great seas, and they have learned to bring in the whaleboats to Tristan's rough shingle beaches and rockstrewn cliffs in a way which even to my sailor's eye is uncanny.

A hunk of kelp, as thick as a man's body, and perhaps twenty feet long, drifted past. We were about five miles from Tristan, which is ringed by a huge barrier of kelp. Inside that barrier the sea is tamed by the fronded fetters to a grey sullenness. Sea mystery! In that moment I wished that the drifting length of kelp was the pointer to the mystery I had come thousands of miles to try and find, rather than the minute plankton my special net was seeking hundreds of feet below the surface.

Sailhardy seemed to anticipate my thoughts. " Any luck?" he asked.

I shook my head.

The Albatross' Foot! It had a selling title, one of the learned gentlemen of the Royal Society had said, and he was right. That strange, almost mesmeric name was woven into the fabric of my war years, with Sailhardy, with Tristan da Cunha. Little had I thought, the day Sailhardy had come aboard my destroyer in the Tristan anchorage, that he and The Albatross' Foot were to become the star which I had followed actively down-horizon for a dozen years. Before that I had lived with the magic of the name for a further six. Science had never heard of The Albatross' Foot! Nor had I, despite my advanced researches before the war into oceanography. Sailhardy had told me it was the inmost secret of the Tristan islanders. They maintained it was a gigantic warm current which swept down in spring-not every spring, but at irregular intervals-between Africa and South America, bearing countless billions of the microscopic 13 sea creatures called plankton, which are the food of everything in the Southern Ocean, from the smallest fish to the whale.