Object Record
Images
Metadata
Catalog Number |
2009.17 |
Object Name |
Magnetometer |
Title |
Portable Variation Transit, or Magnetometer |
Artist |
Gambey, Henri Prudence |
Place of Origin |
France |
Date |
1836-38 |
Description |
Brass variation transit instrument (magnetometer), in oak box. Instrument has two telescope assemblies. |
Label |
Folded into its oak box, this variation transit was small enough for Alexander Dallas Bache to take on summer vacations. For his 1840-43 magnetic survey of Pennsylvania, he made observations at 22 points in Pennsylvania, all at his own expense. Bache, the great-grandson of Benjamin Franklin, was a scientist, superintendent of the United States Coast Survey, and APS member. Specifically interested in geophysical research, he built a magnetic observatory at Philadelphia's Girard College. Bache probably purchased this instrument in Europe in the 1830s when he joined the "magnetic crusade" – an attempt by scientists all over the Western world to chart the constant changes in the earth's magnetic field. Henri Prudence Gambey, a well-known French mathematician and instrument maker, designed this transit. Gambey provided instruments to the French government and to European and American scientists. |
Material |
Instrument: brass and wood; Box: oak |
Credit line |
American Philosophical Society. Gift of the Carnegie Institution of Washington, 2003. |
Search Terms |
surveying measurement 19th century nineteenth century science scientific instrument astronomy optics |