[Choosing to become a geophysicist was] entirely accidental and was due to the difficulty of getting a job during the depression. There happened to be one available in Cambridge at the time when I needed it.

I suspect that the most important effect of World War II on physical science lay in the change in the attitude of people to science. The politicians and the public were convinced that science was useful and were in no position to argue about the details. A professor of physics might be more sinister than he was in the 1930s, but he was no longer an old fool with a beard in a comic-strip. The scientists or at any rate the physicists, had changed their attitude. They not only believed in the interest of science for themselves, they had acquired also a belief that the tax-payer should and would pay for it and would, in some unspecified length of run, benefit by it.

If weak or fallacious arguments are mixed with strong ones, it is natural for opponents to refute the former and to believe that the whole position has been refuted.

Most of the scientists in their twenties and thirties who went in 1939 to work on wartime problems were profoundly affected by their experience. The belief that Rutherford's boys were the best boys, that we could do anything that was do-able and could master any subject in a few days was of enormous value.

Sir Edward has calculated that quick-growing Indian eucalyptus trees have a yield of nine and one-quarter tons of wood an acre a year. As the wood contains 0.8 per cent of the solar energy reaching the ground in the tropics in the form of heat, Sir Edward has suggested that in theory eucalyptus forests could provide a perpetual source of fuel. He has said that by rotational tree planting and felling, a forest of twenty kilometers square would enable a wood consuming power station to provide 10,000 kilowatts of power.

The transition from sea-floor spreading to plate tectonics is largely a change of emphasis. Sea-floor spreading is a view about the method of production of new oceans floor on the ridge axis. The magnetic lineations give the history of this production back into the late Mesozoic and illuminate the history of the new aseismic parts of the ocean floor. This naturally directed attention to the relation of the sea-floor to the continents. There are two approaches: in the first, one looks back in time to earlier arrangements of the continents; in the second, one considers the current problem of the disposal of the rapidly growing sea floor.

There is always a strong inclination for a body of professionals to oppose an unorthodox view. Such a group has a considerable investment in orthodoxy: they have learned to interpret a large body of data in terms of the old view, and they have prepared lectures and perhaps written books with the old background. To think the whole subject through again when one is no longer young is not easy and involves admitting a partially misspent youth.

Sir Edward Bullard maintains that the recent upsurge of keenness in oceanography is correlated with the development of modern sea-sick remedies.