The discussion centers on the relationship between electric arc length, voltage, and capacitance in electrostatic generators. It is suggested that an arc length of 7 cm corresponds to a voltage of approximately 210,000 V, based on the breakdown voltage of air at 20 to 30 kV/cm. Participants debate the role of capacitance, with some arguing that larger spheres can hold more charge and thus produce longer arcs, while others emphasize that capacitance is not solely dependent on size. The conversation also touches on the distinction between sparks and arcs, noting that arcs can be maintained at lower voltages. Ultimately, the participants seek to clarify the underlying physics and mathematical relationships governing these phenomena.