If a wand was attached to the instrument at this point and offered up to the dome, then the electrons drawn up from the ground would be attracted to the positive charge in the dome and spark would be generated. The original machine was invented by physicist Robert J. Van de Graaff at Princeton University and marked the beginning of nuclear research for the civilian applications. It is however, best known for its use as a scientific demonstration tool where the static is used for making peoples hair stand on end or for creating sparks in a similar vein to its earlier counterpart the Wimshurst machine. This example owing to its style of manufacture is an early demonstration model and is probably of Italian origin.
I have found none that are outside of museum or University collections. Jason Clarke Antiques are happy to discuss carriage, condition or for any other queries, alternatively, you can also message me and I will endeavour to come back to you as soon as possible. I have a number of beautiful antiques for sale, so please feel free to browse my other items. The item "EARLY DEMONSTRATION VAN DER GRAAFF GENERATOR BY PHYSICA" is in sale since Thursday, February 13, 2020. This item is in the category "Antiques\Science/Medicine\Scientific Instruments". The seller is "jason750_1" and is located in newbury, Berkshire. This item can be shipped to United Kingdom.