C.H. Errington for Rogers, pin set 15J Chronograph, 1902

Chronographs were also known as "Doctors watches" because the centre seconds hand made it easier to time a persons pulse.

 

This pin set Chronograph is by C.H. Errington of Coventry (...by then owned by Williamson) for G. R. Rogers. The 15 jewel movement has a true English Lever escapement with a Breguet sprung cut compensating balance. The movement, Case and Dial all carry the serial number.

If used as a stop watch the button (at 2 o'clock) stops the seconds hand but also stops the entire movement so the time has to be reset, not an entirely practical proposition.