The Early English North Transept east wall holds two quite different timepieces.

The first is one of Henry Hindley's clocks.  Hindley (1701-1771) created several clocks still running in some of York's historic buildings today.  Some run over a year on a single winding. 

Here's a close-up of the clock face encouraging us (in Latin) to praise the lord.  Curious that Hindley would use Latin as the Anglican Book of Common Prayer should have removed the language from liturgical use by his day.  Note also the IHS Christogram (derived from the first three Greek letters in Jesus.)   

Just to the North of Hindley's clock is a timepiece 300 years newer: the 1955 Astronomical Clock.  At the center of the Green globe is the footprint of the Minster (in gold) surrounded by the city walls.  This would be how the RAF squadrons would see this area as they headed south to bomb Germany during World War II.  The circle above represents the sunrises and sunsets at the exact times throughout the year.  The zodiac signs represent stars used by the navigators to find their way.  As you'd expect, this clock is a memorial to the RAF members who flew to Germany from the Yorkshire area but never returned.