These glass jars are mainly meant for fun. The hollow jars are in different ways covered with tin foil nearly touching each other. One of the flasks has a foiling arranged in a brick-work pattern (488) and another one has foil in a spiral pattern (487). There is also a jar with three bands of foil (486). When such a jar is connected to a voltage source, sparks will jump between the pieces of tin foil lying closest to each other. Thus, because of the different patterns of the foil, different patterns of light will be formed.
Flicker jar; no electrodes
1775 - 1799