electromagnetic rotation device
Date1850-1890
Inventory NumberDW0393
ClassificationElectromagnetic Apparatus
Subject
Maker
Breton Frères
fl. 1843 - 1884
Cultural Region
Place of Origin
Dimensions38.5 × 25 × 15.5 cm (15 3/16 × 9 13/16 × 6 1/8 in.)
Material
DescriptionCoil of fabric-insulated wire wound on iron bar mounted with an axle through its midpoint. Axle joins the two ends of a forked brass frame which can be leaned to correspond with the angle of the earth's magnetic field.
The axle of the iron bar inserts into a pair of point bearings on either end of the fork frame. On the other side of the bearings are knobs that may adjust the bearing. The frame is mounted on a brass column with a cylindrical joint to adjust the inclination of the axis of rotation.
The coil is connected to the frame through a commutator consisting of a metal disc, most likely copper, mounted around the axle on the iron bar, another disc mounted on the right end of the brass fork, and two metal strips that serve as brushes. On the other side of the right end of the fork is a flat piece of metal that looks like a crank shaft, at the end of which is a binding post. The binding post is connected to another coiled wire with fabric insulation. This leads to another binding post, which is connected via a copper strip to another binding post on the right front corner of the base. The binding post on the left front corner of the base connects by a copper strip to the fork, thus completing the circuit.
All mounted on a polished wood base. An old laboratory label reads "13A."
The axle of the iron bar inserts into a pair of point bearings on either end of the fork frame. On the other side of the bearings are knobs that may adjust the bearing. The frame is mounted on a brass column with a cylindrical joint to adjust the inclination of the axis of rotation.
The coil is connected to the frame through a commutator consisting of a metal disc, most likely copper, mounted around the axle on the iron bar, another disc mounted on the right end of the brass fork, and two metal strips that serve as brushes. On the other side of the right end of the fork is a flat piece of metal that looks like a crank shaft, at the end of which is a binding post. The binding post is connected to another coiled wire with fabric insulation. This leads to another binding post, which is connected via a copper strip to another binding post on the right front corner of the base. The binding post on the left front corner of the base connects by a copper strip to the fork, thus completing the circuit.
All mounted on a polished wood base. An old laboratory label reads "13A."
Signedon plaque on base: BRETON FRÈRES / Paris / Rue Dauphine, 23
Inscribedold laboratory label on base: 13A
FunctionWhen batteries are connected to the magnet, the wire-wrapped iron bar will become magnetic. It will then begin to rotate until the north pole dips in the direction of the magnetic field. If the instrument is properly calibrated, the pole reverser will reverse polarity at that moment, the north pole will become the south pole, and the bar will rotate 180 degrees. Polarity will reverse again, and so on.
ProvenanceDavid Wheatland purchased from Alain Brieux, Paris, August 6, 1968 (lot 32/8).
Breton Frères
Date: 1850-1890
Accessories: foot broken off
Object number: DW0392
Ducretet et Lejeune
Date: 1892-1896
Object number: DW0089
English
Date: circa 1820
Accessories: wooden case
brass frame with points
glass arm
handle
broken glass (in package)
Object number: DW0504
French
Date: circa 1880
Accessories: protecting case with glass window
Object number: DW0095
Clemens Kohl
Date: after 1780
Object number: 1998-1-1105
