“When you sit in a chair, you are not actually sitting there, but levitating above it at a height of one angstrom (a hundred millionth of a centimetre), your electrons and its electrons implacably opposed to any closer intimacy.”

“Protons give an atom its identity, electrons its personality.”

“To be sure, Wegener made mistakes. He asserted that Greenland is drifting west at about 1.6 kilometres a year, a clear nonsense. (Its more like a centimetre.)”

“As we parted at the Natural History Museum in London, I asked Richard Fortey how science ensures that when one person goes there's someone ready to take his place.He chuckled rather heartily at my naiveté. 'I'm afraid it's not as if we have substitutes sitting on the bench somewhere waiting to be called in to play. When a specialist retires or, even more unfortunately, dies, that can bring a stop to things in that field, sometimes for a very long while.'And I suppose that's why you value someone who spends forty-two years studying a single species of plant, even if it doesn't produce anything terribly new?''Precisely,' he said, 'precisely.' And he really seemed to mean it.”

“Distance changes utterly when you take the world on foot. A mile becomes a long way, two miles literally considerable, ten miles whopping, fifty miles at the very limits of conception. The world, you realize, is enormous in a way that only you and a small community of fellow hikers know. Planetary scale is your little secret.Life takes on a neat simplicity, too. Time ceases to have any meaning. When it is dark, you go to bed, and when it is light again you get up, and everything in between is just in between. It’s quite wonderful, really.You have no engagements, commitments, obligations, or duties; no special ambitions and only the smallest, least complicated of wants; you exist in a tranquil tedium, serenely beyond the reach of exasperation, “far removed from the seats of strife,” as the early explorer and botanist William Bartram put it. All that is required of you is a willingness to trudge.There is no point in hurrying because you are not actually going anywhere. However far or long you plod, you are always in the same place: in the woods. It’s where you were yesterday, where you will be tomorrow. The woods is one boundless singularity. Every bend in the path presents a prospect indistinguishable from every other, every glimpse into the trees the same tangled mass. For all you know, your route could describe a very large, pointless circle. In a way, it would hardly matter.At times, you become almost certain that you slabbed this hillside three days ago, crossed this stream yesterday, clambered over this fallen tree at least twice today already. But most of the time you don’t think. No point. Instead, you exist in a kind of mobile Zen mode, your brain like a balloon tethered with string, accompanying but not actually part of the body below. Walking for hours and miles becomes as automatic, as unremarkable, as breathing. At the end of the day you don’t think, “Hey, I did sixteen miles today,” any more than you think, “Hey, I took eight-thousand breaths today.” It’s just what you do.”

“In the morning I awoke early and experienced that sinking sensation that overcomes you when you first open your eyes and realize that instead of a normal day ahead of you, with its scatterings of simple gratifications, you are going to have a day without even the tiniest of pleasures; you are going to drive across Ohio.”

“I became quietly seized with that nostalgia that overcomes you when you have reached the middle of your life and your father has recently died and it dawns on you that when he went he took some of you with him.”