Mellon Fountain is a beautiful tribute in bronze, granite, and quartz to Andrew Mellon, a wealthy industrialist, statesman, and founder of the National Gallery of Art. The gallery sits across Constitution Avenue just a short walk from the fountain. Sculpted by Sidney Waugh, the fountain features three nested bronze basins that allow water from a 20-foot spouting jet to cascade from the smaller center basins into larger circular basins below—and ultimately into a fourth granite basin at the bottom. The largest of the bronze basins is adorned with the signs…