Ramsden-type plate electric machine
Date1864-1877
Inventory NumberDW0300
ClassificationElectrical Machine
Subject
Maker
Eugène Ducretet
1844 - 1915
Cultural Region
Place of Origin
Dimensions140 x 96 x 54.7 cm (55 1/8 x 37 13/16 x 21 9/16 in.)
Material
Bibliography
DescriptionThe large glass disk is fixed at the center and rotates with the help of a crank. The disk is compressed by four cushions on springs (Steiner model). The disk passes through two connectors made in the shape of a horse shoe. They are terminated by a piece-like comb and teeth made of brass. These two connectors are attached to two horizontal brass tubes. The latter are connected in turn to a set of brass tubes on which electricity is gathered and used for experiments.
This system of communicating brass tubes is supported by four insulated glass pillars. Above the name plate there is a small removable brass pin used to de-electrify the machine at the end of an experiment (from pin to body to the earth). The whole structure is supported by a table on four legs.
This system of communicating brass tubes is supported by four insulated glass pillars. Above the name plate there is a small removable brass pin used to de-electrify the machine at the end of an experiment (from pin to body to the earth). The whole structure is supported by a table on four legs.
In Collection(s)
Signedon name plate: E. DUCRETET, Rue des Ursulines 21, PARIS
Curatorial RemarksHere is how Ducretet described this machine in his 1870 Catalogue: "#1082 Machine électrique, même modèle, ayant [un plateau de] 50 centimètres 250 FF... Machine électrique de Ramsden, sur table en noyer verni naturel, ou acajou, deux conducteurs; coussins à ressorts, système de Steiner. Deux quarts de cercle en taffetas; électromètre à cadran, boule pour la répulsion des corps légers..." The quadrants and electrometer appears to be missing from this example.
FunctionAn electrostatic machine is an instrument used to produce electricity for conducting serious as well as pedagogical, fun and surprising experiments. The electricity is produced by friction, in this case by the glass disk rotating on the four spring cushions. The electricity is gathered by the comb and teeth device by way of induction and is accumulated on the surface of the brass sphere in the center of the machine.
ProvenanceDavid Wheatland purchased from Roux-Devillas Paris, March 1, 1967 (lot 6/1204).
Constant Vérick
Date: circa 1880
Accessories: eyepieces (2); clear glass slides (3); flat case
Object number: 2002-1-0066
Joseph Zentmayer
Date: circa 1880
Accessories: Zentmayer objective with cannister: 1 1/2; paired oculars (3); Bicknell's achromatic condenser; rotating wheel diaphragm; polarizing eyepiece, polarizer by objective; camera lucida; plane glass window and brass socket; monocular tube; parts box with key; standing case with key.
Object number: 1015
Eugène Ducretet
Date: mid 19th-early 20th Century
Accessories: Includes a hinged, lined case, with latch closures, and a leather strap coiled and attatched to case.
Object number: 1998-1-0809