Hour Recording Chronograph.     Chronograph Functions index

Timing to 1/5 second [C]. 

Timing up to 30 minutes [D].
Timing telephone conversations [E]. 

Timing up to 12 Hours

The dial of this chronograph is calibrated for timing 1/5 second. Timing up to 30 minutes, or in some cases 45 minutes, is possible with a minute recording chronograph. For each rotation of the chronograph hand the minute-recording hand moves one division. Both hands return to zero simultaneously. Charges for telephone calls are usually based on periods of 3 minutes; the special 3rd, 6th and 9th minute divisions show at a glance the number of three-minute periods that have elapsed.

F = Hour recorder