A single turn suffices, however, to demonstrate Oersted's experiments, using small strips of zinc and copper dipped in ammonium-chloride solution.
"The Earliest Electromagnetic Instruments"
Robert A. Chipman
He noted that the size of the cell plates and the nature of the cell's moist conductors would certainly have a great effect, but that to investigate these in detail would take undue time, and he therefore proposed to keep this part of the apparatus constant, using one pair of zinc and copper plates 3.6 inches in diameter, separated by cloth soaked in ammonium-chloride solution.
"The Earliest Electromagnetic Instruments"
Robert A. Chipman
These must contain compounds of N, P, and K. N is usually applied in the form of ammonium compounds, e.
"An Introduction to Chemical Science"
R.P. Williams