Note 4 — Chapter LXII · INDICATING DEVICES

NOTE.—The author adheres to the term virtual because in mechanics the adjective effective is used to denote the difference of two opposing forces; for instance, at any instant in the operation of a steam engine, effective pressure = forward pressure - back pressure, hence, to be consistent in nomenclature, the term effective cannot be used for the forward or virtual pressure, that is, the pressure impressed on an electric circuit.