Please help, how can i calculate the capacitance of a kelvin water dropper? This is all i have from my experiment

At a distance of 0.5 mm, the spark occurs most frequently, every 1.5 seconds. At a distance of 1 mm, the spark occurs every 3 seconds. At a distance of 2 mm, the spark occurs every 7 seconds. At a distance of 3 mm, the spark occurs every 19 seconds. Beyond 3 mm, the spark either does not occur or does not occur at a regular interval. Most likely due to unintended interactions outside the system defined in the procedure. Distance (m Beyond 3 No interval where spark occurs