280665

Information

• Patent Grant
• 280665

• References
• Source

• Patent Number

  280,665

• Date Filed

  Not available

• Date Issued

  Tuesday, July 3, 1883
  141 years ago

• CPC

  • G01J1/14 - using comparison with a surface of graded brightness
  • G01N21/293 - with colour charts, graduated scales or turrets

• US Classifications

  • 356 - Optics: measuring and testing