Side view showing the comb collectors between the 65 inch glass plates and the auxiliary battery of 135 Leyden jars. The large electrostatic generator (Van Marum electriseermachine) is a large handcrafted electromechanical instrument designed by Martin van Marum and built by John Cuthbertson in 1784 for the Teylers Museum in Haarlem, where it forms the centerpiece of the instrument room. A 2 ft spark could be produced (roughly 330.000 volts). John Cuthbertson (1743-1821) was an English instrument maker and inventor who lived from 1768-96 in Amsterdam. In 1782 Cuthbertson published a book in Dutch called Algemeene Eigenschappen van Electriciteit, onderrichting van de Werktuigen en het nemen van proeven in dezelve (General characteristics of electricity, education on the tools and the performing of tests in those) and organized public lectures to disseminate the knowledge about electricity. He produced a number of smaller electrostatic generators - a design that would be produced until the 1920s.