When I was 9, we packed up our home in Los Angeles and arrived at Heathrow, London on a gray January morning. Everyone in the family settled quickly into the city except me. Without my beloved beaches and endless blue-sky days, I felt at a loss and out of place. Until I made a discovery.

Southbank, at an eastern bend in the Thames, is the center of British skateboarding, where the continuous crashing of skateboards left your head ringing. I loved it. I soon made friends with the local skaters. We spoke our own language. And my favorite: Safe. Safe meant cool. It meant hello. It meant don’t worry about it. Once, when trying a certain trick on the beam (横杆), I fell onto the stones, damaging a nerve in my hand, and Toby came over, helping me up: Safe, man. Safe. A few minutes later, when I landed the trick, my friends beat their boards loud, shouting: “Safe! Safe! Safe!” And that’s what mattered — landing tricks, being a good skater.

When I was 15, my family moved to Washington. I tried skateboarding there, but the locals were far less welcoming. Within a couple of years, I’d given it up.

When I returned to London in 2004, I found myself wandering down to Southbank, spending hours there. I’ve traveled back several times since, most recently this past spring. The day was cold but clear; tourists and Londoners stopped to watch the skaters. Weaving (穿梭) among the kids who rushed by on their boards, I found my way to the beam. Then a rail-thin teenager, in a baggy white T-shirt, skidded (滑) up to the beam. He sat next to me. He seemed not to notice the man next to him. But soon I caught a few of his glances. “I was a local here 20 years ago,” I told him. Then, slowly, he began to nod his head. “Safe, man. Safe.”

”Yeah,” I said. “Safe.”

“We did a test run one day in August, and decided to give it a go. To be honest, I thought he’d blink (眨眼)after it got really cold or rainy, but he never did,” Jonathan said. He recalled one day when the weather was particularly bad. “It’s really raining out there today,” he told Simon. “And Simon said, ‘Well then we’re going to get wet!’ He took pride in toughing it out, and it became a really fun family routine.”

In the 1750s the Swedish chemist Karl Scheele was the first person to find a way to produce phosphorus. He in fact discovered eight more chemical elements including chlorine , though he didn't get any praise for them. He was a very clever scientist, but his one failing was a curious habit of tasting a little of every substance he worked with. This risky practice finally caught up with him, and in 1786 he was found dead in his laboratory surrounded by a large number of dangerous chemicals, any of which might have been responsible for his death.