This Sunday, we will all dutifully set our clocks back one hour for daylight saving time. But why is our day divided into 24 hours, each hour divided into 60 minutes, and each minute into 60 seconds?

Several correspondents recently pointed out how the division of hours into 60 minutes and minutes into 60 seconds (and a full turn into 360 degrees) is almost certainly based on the Sumerians’ very ...