plate-type frictional electrostatic machine
notes: label: Description (Brief)
content: People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism. Natural philosophers, scientists, and instrument makers created many ingenious devices to generate electrostatic charges starting in the 1600s. These machines varied in size and technique but all involved rotary motion to generate a charge, and a means of transferring the charge to a storage device for use.
label: Description (Brief)
content: In the latter 1700s electrical researchers adopted improved electrostatic machines that replaced earlier glass cylinders with a flat glass plate. This increased the machines’ efficiency by passing the glass plate between leather rubbing pads that increased the contact area. Experience with plate machines brought many design variations with sizes ranging from small table-top units for laboratory use to large cabinets that powered early x-ray machines.
label: Description (Brief)
content: This plate-type electrostatic machine shows a simple cruciform design. Two wooden posts support an axle with a brass hub that holds the glass plate, only a remnant of which remains. The handle on one side turns the axle. A glass post on the short end of the machine holds the rubbing pads, although the leather is missing from the holders. The pads contacted both sides of the plate and provided the friction that generated the charge. A glass post on the long end of the machine holds a brass cylinder called the prime conductor which stores the charge. A ball-tipped, comb threaded into the prime conductor transfers the charge from plate to cylinder.
label: Description (Brief)
content: This machine was collected in 1967 from the Museum of Science and Industry in Chicago. While obviously made for bench-top use we do not know exactly when it was made or by whom. However, the machine is similar in design to a larger machine in the museum’s collection that was made in the mid-1800s by Nathan B. Chamberlain. (Catalog #325971)
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
creditLine: label: Credit Line
content: from the Museum of Science and Industry (Chicago)
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.271855.07
label: accession number
content: 271855
label: collector/donor number
content: 31.324B
label: catalog number
content: 271855.07
objectType: label: Object Name
content: Electrostatic Machine
label: Object Name
content: electrostatic generator
label: Other Terms
content: Electrostatic Machine; Electrostatic Devices
physicalDescription: label: Measurements
content: overall: 21 1/4 in x 17 in x 44 in; 53.975 cm x 43.18 cm x 111.76 cm