 The voltaic pile consisted of pairs of copper and zinc discs piled on top of each other, separated by a layer of cloth or cardboard soaked in brine (i.e., the electrolyte).Unlike the Leyden jar, the voltaic pile produced a continuous electricity and stable current, and lost little charge over time when not in use, though his early models could not produce a voltage strong enough to produce sparks.He experimented with various metals and found that zinc and silver gave the best results.