For more than a century a family in London sold the time. John Henry Belville began in 1836, his widow Maria carried it on, and from 1892 their daughter Ruth took over. Once a week she walked to the Royal Observatory at Greenwich, set her pocket chronometer by the master clock, and got a certificate saying how far off it was. Then she went round her customers, mostly clockmakers by the end, and let them set their own clocks by hers. The watch was an old John Arnold chronometer, and she called it Arnold. She kept at it until about 1940, long after telegraph wires, and then the six pips on the radio, could bring Greenwich into a room. What she sold was never really the hour, which was free. It was a woman who had been to Greenwich that week, and could show you the paper.