2188821

Information

• Patent Grant
• 2188821

• References
• Source

• Patent Number

  2,188,821

• Date Filed

  Not available

• Date Issued

  Tuesday, January 30, 1940
  85 years ago

• CPC

  • G01C17/24 - Illumination

• US Classifications

  • 362 - Illumination
  • 033 - Geometrical instruments
  • 246 - Railway switches and signals
  • 385 - Optical waveguides