Lourie completed his trip. It took him three weeks and marked the first time anyone has traveled from the source of the Hudson to the mouth in a single vessel. The Hudson proved to be a very changeable river. It includes seven locks and nine power dams. The northern half is a true river with strong current, but the lower half is tidal, a sunken river from the days of glaciers. In its first 165 miles, it drops more than 4,000 feet to Albany. The second...