Pendulum Problem

Exploration Stage: Observatory
From: Isabelle
Description: I noticed a trace of sparks on the pendulum lying on the City’s old star chart. Let’s go and examine it. I’m sure the pendulum and the chart will tell us whose soul is caught in the phylactery.
Completed: Helen and I built this pendulum to calculate the length of a day in the City. The fog covers the sky here, so the calculations have to be done blindly. I wonder why the soul was attracted to this item. Can it be that it’s associated with the City’s fog?