There are three stages in scientific discovery. First, people deny that it is true, then they deny that it is important; finally they credit the wrong person.

When the poet Paul Valery once asked Albert Einstein if he kept a notebook to record his ideas, Einstein looked at him with mild but genuine surprise. "Oh, that's not necessary," he replied . "It's so seldom I have one.

I have long known that it is part of God's plan for me to spend a little time with each of the most stupid people on earth.

18th century scientists, the French in particular, seldom did things simply if an absurdly demanding alternative was available.

Language is more fashion than science, and matters of usage, spelling and pronunciation tend to wander around like hemlines.

It was the kind of pure, undiffused light that can only come from a really hot blue sky, the kind that makes even a concrete highway painful to behold and turns every distant reflective surface into a little glint of flame. Do you know how sometimes on very fine days the sun will shine with a particular intensity that makes the most mundane objects in the landscape glow with an unusual radiance, so that buildings and structures you normally pass without a glance suddenly become arresting, even beautiful? Well, they seem to have that light in Australia nearly all the time.

But I got a great deal else from the experience. I learned to pitch a tent and sleep beneath the stars. For a brief, proud period I was slender and fit. I gained a profound respect for the wilderness and nature and the benign dark power of woods. I understand now, in a way I never did before, the colossal scale of the world. I found patience and fortitude that I didn't know I had. I discovered an America that millions of people scarcely know exists. I made a friend. I came home.