What influence has the kind of metal used upon the spark discharge of an electrically charged object? That question can simply be answered by this discharge rake, consisting of four spikes of copper, iron, zinc and brass respectively. Because of the difference in electric conductivity of the metals, a spark will be generated earlier at the copper spike than, for example, at the iron spike. The beautifully blown, glass handle serves as insulator.
Discharge rake (spikes made of copper/ iron/ zinc/ brass)
circa 1850 - 1874