In the early 18th century, when a handmade pocket watch was the ultimate luxury for a gentleman, master clockmakers engineered one that could tell time at night, even after the candles had been extinguished. With the touch of a button, the divinely complex mechanism would chime a mellifluous pattern counting off the hour, and then, in increments of five, the minutes. Baume & Mercier’s new Clifton 1830 pocket watch is an updated version of that marvel, showcasing the five-minute repeater, a ‘‘complication’’ long vaunted by aficionados. The Swiss house has made just 30, set in 18-karat red gold. It makes telling time by the glaring face of a smartphone seem strangely passé.