The larger the current in the coils around the iron core, the stronger the magnetic field. The current in the coils around the iron core was inversely proportional to the number of coils used. The iron core became permanently magnetic after current was passed through it one time. A wire connects the two pieces of metal, and the two solutions are connected by a salt solution bridge. Electrons flow from right to left because the zinc ions are releasing electrons to the copper metal anode.
Electrons flow from right to left because zinc metal acts as the cathode and gets reduced.
Electrons flow from left to right because the copper cathode loses electrons more easily than zinc. Electrons flow from right to left because the zinc metal anode gives up electrons to copper ions through the copper cathode. It was necessary to add more cells to a battery in order to send telegraph signals over longer distances because More resistance was required since longer lines created more current. The resistance increased with distance and increased voltage provided sufficient current . Less voltage per cell made the line more efficient and cheaper to run.