A few weeks ago, my wife and a couple friends participated in The Great Saunter, a 30+ mile circumnavigation of Manhattan along the city’s Waterfront Greenway, and reported that they had had a great time. This seemed like a promising exercise for me, too, and not just for the training miles, but also for the experience of circling the island, which I had never done before. Accordingly, last Saturday morning after a cappuccino and a handful of mixed nuts, I headed out to Riverside Park on Manhattan’s west side. It was a beautiful, clear spring morning, with the forecast calling for sunny skies and moderate temperatures, although as I would learn later the temperature would peak at 91 F.