"However, with sunset and sunrise changing throughout the year, this meant the hour had to move with the seasons, expanding in summer and contracting in winter. These so-called temporal hours were inherited by Europians in the Midle Ages and meant that the length of the hour in London, for example, could vary from 38 to 82 minutes.(..)

A fourteenth-century cookbook, for example, instructs readers to boil an egg by advising that they leave it in the water 'for the length of time wherein you can say a Miserere'. This is the 51st Psalm of the Bible and a plea for clemency that begins with the words 'Have mercy upon me, O God' - a nice bit of piety that I've found produces a rather runny egg."

James Vincent, Beyond Measure, 2022.