Robert Balmer

I am trying to measure low level (pA) electrostatic current with me 6517B  electrometer. The electrostatic current is generated by a plate moving in liquid petroleum. The electrometer is mounted on the moving plate so no cables flex during the motion (see attached illustration). Obviously there is a varying capacitance in this arrangement. When the experiment is run without a liquid present between the plates the 6517B shows (detects) a varying current, but there should be no current in this situation. Is the electrometer producing a false reading that results from the varying capacitance?
Current is the rate of flow of charge, the relation for the charge in the capacitor is: Q = CV.  If we differentiate this relation with respect to time, we get a relationship for current (i) through the capacitor. i = dQ/dt = d(CV)/dt = C(dV/dt) + V(dC/dt).
So, if there is a voltage across a capacitor and the capacitance changes (e.g., the distance between the capacitor’s plate’s changes) then a current will be induced.

Is this what is happening?