Reading how Galileo measured time in the experiment with inclined plane, it says on Wikipedia, that:
Galileo accurately measured these short periods of time by creating a pulsilogon. This was a machine created to measure time using a pendulum. The pendulum was synchronized to the human pulse. He used this to measure the time at which the weighted balls passed marks that he had made on the inclined plane.
However, I am unable to find any drawing or reference to what it actually looked like.
According to other source I found, Galileo actually used a guitar and by listening to string rhythms/frequencies he could measure subseconds intervals.
Does anyone have a reference to how it really was?