the minute hand was added to clocks in 1730s.
the minute hand was added to clocks in 1730s.
when was the minute hand added to clocks?
1730s
these early clocks, due to their verge escapements, had wide pendulum swings of 80–100°. in his 1673 analysis of pendulums, "horologium oscillatorium", huygens showed that wide swings made the pendulum inaccurate, causing its period, and thus the rate of the clock, to vary with unavoidable variations in the driving force provided by the movement. clockmakers' realization that only pendulums with small swings of a few degrees are isochronous motivated the invention of the anchor escapement around 1670, which reduced the pendulum's swing to 4–6°. the anchor became the standard escapement used in pendulum clocks. in addition to increased accuracy, the anchor's narrow pendulum swing allowed the clock's case to accommodate longer, slower pendulums, which needed less power and caused less wear on the movement. the seconds pendulum (also called the royal pendulum), 0.994 m (39.1 in) long, in which the time period is two seconds, became widely used in quality clocks. the long narrow clocks built around these pendulums, first made by william clement around 1680, became known as grandfather clocks. the increased accuracy resulting from these developments caused the minute hand, previously rare, to be added to clock faces beginning around 1690.
pendulum clock
it was reported that by 1855 that 98 percent of towns and cities had transferred to gmt. on the other hand, not all railway companies convinced the local dignitaries to bring their clocks on public buildings in line without stern resistance. although by 1844 the bristol and exeter railway was running to london time, the public clocks at both exeter and bristol operated to local time but showed london time by a second minute hand, 14 and 10 minutes ahead, respectively, of its companion. in exeter this situation arose due to the reluctance of the dean of exeter cathedral to concede to the demands of the railway company, the cathedral clock being the principal timekeeper for the city. similarly, the clock at the bristol exchange installed in 1822 subsequently had a second minute hand added. bristol did not solely recognise railway time until september 1852. it was not for a further eight years and the arrival of the electric telegraph that railway time was the sole time recognised in these towns and others in the west country, including bath, devonport and plymouth. another town that stood its ground was oxford where the great clock on tom tower at christ church, oxford had two minute hands.
railway time