Images(2)

Wimshurst electrostatic machine

Datecirca 1890

Inventory Number1997-1-0644a,b,c

ClassificationElectrostatic Machine

Subject

Maker James W. Queen & Company 1853 - 1893

User Department of Physics, Harvard University founded 1884

Cultural Region

Place of Origin

Dimensions36.9 × 65.4 × 41.5 cm (14 1/2 × 25 3/4 × 16 5/16 in.)

Material

Accessoriestwo fragments of glass wheel bound separately as (b) and (c)

DescriptionA rectangular base supports a cylinder on which is fixed an axle. The axle has two separate set of pulleys linked to the grooved wheel on the side, which is turned by a hand crank. Pieces of the original leather straps are still there. The axle was made for two glass discs to rotate in opposite directions. Both are broken. They have several sectors along they edges covered in what appears to be gold foil. Brushes are used to gather electrostatic charges. On the front are two sliding electrodes, one hand insulated so they can be handled.

The base has an old Harvard inventory number: 8-41. There are also two letters: EQ.

Signedon plaque, script: Jas. W. Queen & Co. / Philada

FunctionThis electrostatic machine invented in the early 1880s uses two glass discs spinning in opposite directions to generate electric charges. The two sliding electrodes found at the front of the instrument are used to distribute charges to other instruments. When put in close-enough distance to one another, the electrodes will produce a small lightning, which results in discharging the apparatus. The closer they are, more frequent will the lightning be since it takes less charge to bridge a short air gap than it takes for a longer one.

For more information, go to the following website.

For a short YouTube movie on how such a machine works, go to the following website.

ProvenanceFrom the Department of Physics, Harvard University.