Sixty-four years ago today, on May 12th, 1931, a search party on the Greenland ice-cap came upon a pair of skis stuck upright in the snow, with a broken ski-pole lying between.
Underneath they found the body of a man of about 50, "his face calm and peaceful, almost smiling". It was that of a wellknown, but as yet not famous, scientist who had had gone missing while on an expedition some months previously. It was Alfred Wegener.
Alfred Lothar Wegener was a German meteorologist who, in the early years of the present century, contributed very significantly to our knowledge of the thermal structure of the upper atmosphere.
But it is not for this he is remembered. In fact, during the later part of his life and for some years afterwards he was regarded as something of a crank; he had a zany idea that the continents had been wandering aimlessly around the surface of the Earth for millions and millions of years.
The concept of "continental drift" was not original to Wegener. As long ago as 1620 the English philosopher Francis Bacon had looked at a map of the world and noticed that Africa and South America appeared capable of fitting together like two adjacent pieces of a jig-saw puzzle.
But Wegener became an ardent champion of the drift theory, proposing it in the first instance in 1912, and developing his ideas in detail in The Origins of Continents and Oceans, published in 1915.
Some 200 million years ago, he maintained, the Earth had only one great land mass, which he called Pangea - "all lands". Then about 180 million years ago it split into two parts, which drifted slowly away from each other.
To the north was Laurasia - North America, Europe and Asia, still joined together; Gondwanaland - comprising South America, Africa, India and Australia - lay to the south. Some 135 million years ago South America began to break away from Africa and the south Atlantic Ocean filled the gap between.
Wegener visualised the continents as large rafts of granite, ploughing in slow motion through a great basaltic sea and throwing up mountains like bow waves on their leading edge. It was a bizarre and courageous theory and was rejected for many years.
It was not until the 1950s that better geological mapping and new techniques for magnetic observations made it clear that at one time the continents had indeed been joined together.
But at the time of Wegener's lonely death in Greenland in 1930, his ideas about the moving continents were regarded as merely another amusing demonstration of his well-known eccentricity.