Corbett's electrostatic machine

Close-up of metal rake + glass tumbler. Leyden jar storage battery is to the right.

The electrostatic machine was made by a Shaker pharmacist named Thomas Corbett in 1810 for medical treatment.[1] Corbett was medical physician for the Shakers, a religious group of colonial America. He was a botanist and used herbal medicines and unorthodox medical "cures" for his patients, including electricity.[2]

Corbett's electrostatic machine consists of a 0.5-inch (13 mm) wooden base platform sitting on a 2-inch (51 mm) frame, forming a box. The wooden platform is about 12 inches (300 mm) wide and about 9 inches (230 mm) deep. To one side of the wooden platform is mounted a small axle on pivots, which holds a rotating glass jar cylinder about the size of a Mason jar. This glass jar is attached to a crank wheel of about 5 inches (130 mm) with a leather belt. The crank wheel can be turned by hand. The wooden platform also contains a Leyden jar-style battery in one corner, standing some 9 inches (230 mm) high. The battery is a glass receptacle with a metal rod in the center, covered by a metal ball on top which collects and releases a high voltage electrical charge.[3]

The crank wheel is turned by an operator using the knob handle and then the glass cylinder would rotate by an attached belt. The glass jar then rubs against a layered silk cloth pad or a textile cloth pad, developing a high-voltage positive electrical charge. This static electricity charge is then taken off the glass cylinder through a small metal rake and transferred by wire to the Leyden jar storage battery for later use (see close-up illustration).[3] The high voltage stored electrostatic charge kept in the Leyden jar was then on the metal ball on top of the glass storage battery. It would produce a spark visible to the eye when the set of small metal globes attached to the battery were brought close enough to each other as a test experiment in a discharge.[4] The electrical principles of Corbett's electrostatic machine were later used by Edison.[4][5][6]

The high voltage static charge on top of the Leyden jar storage battery was applied to a patient as he or she sat on a chair or stool atop a special platform. The four glass legs of the chair insulated the platform from the ground. The operator channeled the stored charge from the Leyden jar to the patient using metal attachments that were connected to the patient. The electrical charge produced a shock that was described to have been similar to "touching a doorknob after walking across carpet in dry weather".[3]

The electrical treatment from Corbett's electrostatic machine supposedly "cured" the sufferer of a variety of illnesses, or at least had some electrotherapeutic value.[7] It was especially designed to treat rheumatism.[7] More likely, however, the electrical shock temporarily diverted the sufferer's mind from his or her aches and pains.[8] Shaker Elizabeth Lovegrove recorded in a journal in 1837 that an elder sister of the Shakers was being treated by the Corbett machine. She reported that the Nun felt better after each treatment, at least temporarily.[8]

• Franklin's electrostatic machine

Citations

Sources

• Cohen, Brenda H. (1998). America's Scientific Treasures: A Travel Companion. American Chemical Society. ISBN 0841234442.
• Miller, Amy Bess Williams (1999). Shaker Medicinal Herbs: A Compendium of History, Lore, and Uses. Storey Books. ISBN 1580170404.
• Shea, John Gerald (1992). Making Authentic Shaker Furniture: With Measured Drawings of Museum Classics. Courier Corporation. ISBN 0486270033. While believed to have electrotherapeutic value, it proved principles later applied by Thomas Edison.
• Sprigg, June (1990). By Shaker Hands: The Art and the World of the Shakers. University Press of New England.
• Swank, Scott T. (1999). Shaker Life, Art, and Architecture: Hands to Work, Hearts to God. Abbeville Press. ISBN 0789203588.
• Williams, John S. (1971), The Shaker Museum, Shaker Museum Foundation