Faraday apparatus
Date1860-1880
Inventory Number1997-1-0255a
ClassificationElectromagnetic Apparatus
Subject
Attributed to
Heinrich Daniel Ruhmkorff
1803 - 1877
Cultural Region
Dimensions38.5 x 60 x 25 cm (15 3/16 x 23 5/8 x 9 13/16 in.)
Material
Accessoriesinstrument parts of various shapes and sizes (b)
Bibliography
DescriptionThis magnetic solenoid consists of four gilded steel feet screwed sideways support the instrument. It consists mainly of two large perforated iron cylinders on which coils have been wound around. Their axes are in the same horizontal line. When electricity passes through the coils (from the connectors at each end of the instrument), it creates a powerful magnetic field inside the longitudinal cavities. The two cylinders can slide away from each other, a scale indicating in millimeters the empty space between them. Two large wingnuts underneath the base fixed the cylinders in place.
Signedunsigned
FunctionWas used to measure the Verdet constant of materials. It is an optical constant. To measure it, a beam of light was sent in the horizontal axis of the two cylinders towards a transparent material, passing within the strong magnetic field generated by the apparatus. Simply said, Emile Verdet discovered that the rotation of the plane of polarization is proportional to the strength of the magnetic force.
A video demonstration of a Ruhmkorff electromagnet by the Fondazione Scienza e Tecnica in Florence is available on Youtube here.
A video demonstration of a Ruhmkorff electromagnet by the Fondazione Scienza e Tecnica in Florence is available on Youtube here.
Accessories: 7 cases of varying shapes and sizes
Object number: 1998-1-1126
Date: 1940
Accessories: contains 24 metal rods of different shapes and sizes; 4 pulleys (?) & 1 cardboard circle with plastic film, and other asst. unidentifiable parts
Object number: 1998-1-0643
W.G. Pye & Company, Ltd.
Date: circa 1920
Accessories: 5 accessory parts:
2 magnetic rods with spherical ends;
one brass notch;
needle with tip inserted into cork;
Object number: 1997-1-0662
Walter Hibbert
Date: early 20th Century
Accessories: 7 accessory parts:
2 magnetic rods with spherical ends;
4 brass notches;
needle with tip inserted into cork;
Object number: 1997-1-0661
Rudolph Koenig
Date: circa 1865
Object number: 1997-1-0892d
Rudolph Koenig
Date: circa 1865
Object number: 1997-1-0892c
Rudolph Koenig
Date: circa 1865
Object number: 1997-1-0892g