flowing in a streaming cell if the electrodes, which are supposed to be ideally depolarized,
are short-circuited. 
is positive if the current in the membrane, plug, etc., is from high to low pressure side (and in the outside lead from low
to high pressure side).
Source:
PAC, 1972, 31, 577
(Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix
II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry)
on page 620