Pulse watch

By now clocks could tell time to the nearest minute, so minute hands were added to clocks in the late 17th century. Floyer invented a device which when wound would run for exactly 60 seconds. This allowed to calculate heart rate for the first time!
 John Floyer England 1707 Pulse watch

By now clocks could tell time to the nearest minute, so minute hands were added to clocks in the late 17th century. Floyer invented a device which when wound would run for exactly 60 seconds. This allowed to calculate heart rate for the first time!