Note 36 — ON THE FUNDAMENTAL CONCEPTS OF ELECTROSTATICS.[26]
Thomas J. (Thomas Joseph) McCormack translation
The arrangement described is for several reasons not fitted for the actual measurement of potential. Thomson's absolute electrometer is based upon an ingenious modification of the electrical balance of Harris and Volta. Of two large plane parallel plates, one communicates with the earth, while the other is brought to the potential to be measured. A small movable superficial portion f of this last hangs from the balance for the determination of the attraction P. The distance of the plates from each other being D we get V = D√(8πP/f).