Object Details
- Max Kohl
- Description
- Michael Faraday found that the magnetic force of the earth could induce electrical currents in metallic bodies in motion. Building on this idea, Charles Delezenne in France introduced an earth inductor in 1844.
- The inscriptions on this instrument read "MAX KOHL Werkstätten für Prazisions Mechanick CHEMNITZ I.S." and "CENTRAL SCIENTIFIC CO. LABORATORY APPARATUS CHICAGO U.S.A." Kohl described it as an "Earth Inductor after Palmieri...with round frame 300 mm diameter, with 100 turns of 1 mm thick wire, with commutator." Luigi Palmieri was a physicist in Naples who, in the 1840s, developed an earth inductor with elliptical ring that rotated around its longer axis. The Palmieri apparatus with a circular ring, as in this example, seems to have originated in the 1860s.
- Max Kohl was in business as a scientific instrument maker from 1876 to 1937. The Central Scientific Co. was established in 1900. This example belonged to Trinity College in Hartford, Conn., and came to the Smithsonian in 1981.
- Ref: Max Kohl, Physical Apparatus (Chemnitz, 1926), p. 974.
- Location
- Currently not on view
- Credit Line
- Trinity College, Department of Physics
- ID Number
- 1981.0743.04
- accession number
- 1981.0743
- catalog number
- 1981.0743.04
- Object Name
- earth inductor or Palmieri apparatus
- Physical Description
- wood (overall material)
- metal (part material)
- Measurements
- overall: 15 3/4 in; 40.005 cm
- overall: 17 in x 19 1/4 in x 11 3/4 in; 43.18 cm x 48.895 cm x 29.845 cm
- Place Made
- Germany: Saxony, Chemnitz
- See more items in
- Medicine and Science: Physical Sciences
- Science & Mathematics
- Measuring & Mapping
- National Museum of American History
- Subject
- Science & Scientific Instruments
- Science & Scientific Instruments
- Record ID
- nmah_1030889
- GUID (Link to Original Record)
- https://n2t.net/ark:/65665/ng49ca746a8-e125-704b-e053-15f76fa0b4fa
