electromagnetic rotation bar
Date1850-1890
Inventory NumberDW0392
ClassificationElectromagnetic Apparatus
Subject
Maker
Breton Frères
fl. 1843 - 1884
Cultural Region
Place of Origin
Dimensions32.5 x 28.8 x 16.7 cm (12 13/16 x 11 5/16 x 6 9/16 in.)
Material
Accessoriesfoot broken off
DescriptionTwo brass columns, one twice as tall as the other, supporting an assembly of rotating brass rods, strips of iron, and cups, possibly made of ivory and filled with mercury, all mounted on a wood base with four feet, one broken.
The taller brass column has a cap in the shape of a chalice with an acorn on top. An arm extends out from near the top of the column. At the end of the arm is a screw that adjusts the height of a point bearing. Into that bearing is inserted the point of a thin brass rod that is supported on the other end by a metal piece in the bottom of a cup that is most likely ivory and was most likely filled with mercury at one point. Extending out of the rod and into the cup is a copper wire. A bar magnet is supported by the rod as well. The magnet is bent at 90 degrees in the middle so that the rod passes through it. On the other side of the rod, the magnet bends downward 90 degrees and extends down to the cup.
The shorter column has a head like a chess pawn. Extending out from it is an annular arm through which the magnet-and-rod assembly passes. The arm supports an annular cup, most likely made of ivory, which would most likely be filled with mercury.
There are two binding posts on the base, one of which is connected by a copper strip to the lower cup, the other of which is connected to the shorter brass column.
A pair of brass brackets on either side of the base has slits on their tops that hold an iron strip with a brass sleeve toward one end and points on either end. The strip fits between the two bearings on the assembly.
The taller brass column has a cap in the shape of a chalice with an acorn on top. An arm extends out from near the top of the column. At the end of the arm is a screw that adjusts the height of a point bearing. Into that bearing is inserted the point of a thin brass rod that is supported on the other end by a metal piece in the bottom of a cup that is most likely ivory and was most likely filled with mercury at one point. Extending out of the rod and into the cup is a copper wire. A bar magnet is supported by the rod as well. The magnet is bent at 90 degrees in the middle so that the rod passes through it. On the other side of the rod, the magnet bends downward 90 degrees and extends down to the cup.
The shorter column has a head like a chess pawn. Extending out from it is an annular arm through which the magnet-and-rod assembly passes. The arm supports an annular cup, most likely made of ivory, which would most likely be filled with mercury.
There are two binding posts on the base, one of which is connected by a copper strip to the lower cup, the other of which is connected to the shorter brass column.
A pair of brass brackets on either side of the base has slits on their tops that hold an iron strip with a brass sleeve toward one end and points on either end. The strip fits between the two bearings on the assembly.
Signedon plaque on base: BRETON FRÈRES / Paris / Rue Dauphine, 23
on plaque on base: BRETON FRÈRES
FunctionA circuit is formed between the two binding posts. The current passes through the copper strip, through the mercury in the bottom cup, through the brass rod, through the copper wire coming out of the brass rod, into the mercury in the annular cup, and then through the shorter brass pillar and through the copper wire connecting it to the other binding post.
The current passing through the rod and the pillar causes the lower pole of the magnet to rotate around the current produced in the rod.
The current passing through the rod and the pillar causes the lower pole of the magnet to rotate around the current produced in the rod.
ProvenanceDavid Wheatland purchased from Alain Brieux, Paris, August 6, 1968 (lot 32/7).
Charles-Louis Chevalier
Date: circa 1820
Accessories: (b) glass cup (stored separately on same shelf); (c) long, Y-shaped brass tube (tied to pump)
Object number: DW0822a-c
Thomas Hall
Date: circa 1890
Accessories: pulley rope
Object number: 1997-1-1423
Beckman Instruments, Inc.
Date: circa 1955
Accessories: instructions attached to underside of box lid
Object number: 1996-1-0276
Buff & Buff Manufacturing Company
Date: circa 1905
Accessories: wood case; leather case; right-angle prism; plumb bob; oil flask; tripod (5174b)
Object number: 5174a
Carl Zeiss Jena
Date: circa 1926
Accessories: wooden box with two hook-and-eye latches to fasten front opening; in instrument file: instruction book (photocopy); Geissler tube labeled "H2"; carboard tube containing German thermometer C in stainless steel holder that screws into instrument; glass bottle with cork stopper labeled "Monobromnaphthalin, Germany nD=1 658"; small round cardboard box labeled "For Pulfrich Refractometer" containing one tubulure
Object number: 1996-1-0229
Central Scientific Company
Date: circa 1940
Accessories: 2 Leyden condensers made of Pyrex
One rubber **gutta percha?** pulley, rotted.
Object number: 1997-1-0634
Edward Marmaduke Clarke
Date: 1838-1840
Accessories: 5 objectives for simple microscope; 2 objectives for compound microscope (1 in can; 1 with lieberkuhn); cup diaphragm with lieberkuhn in brass box; brass box of cover slips; stage forceps; tweezers; 2 live boxes; frog plate; bull's eye; fish tube wire; wrench; chamois; 2 unmounted lenses; 40 prepared slides; standing case; 2 keys.
Object number: 1018
See also/See also
