Using the tachymetric scale
Example: calculating the speed of a car. Record the time the car takes to cover a distance of 1 kilometre. Read off the tachymetric scale the speed indicated by the central seconds hand. In this case, the car is travelling at 120 km/h.
Using the pulsimetric scale
Example: calculating the number of heart-beats per minute. Start the chronograph, count the heartbeats and stop it at the beat corresponding to the scale graduations of your chronograph (here to the 30th beat). Read the number of beats per minute off the pulsimetric scale: here, 60 beats/ minute.