1540768

Information

• Patent Grant
• 1540768

• References
• Source

• Patent Number

  1,540,768

• Date Filed

  Not available

• Date Issued

  Tuesday, June 9, 1925
  99 years ago

• CPC

  • G01J3/461 - with colour spinners

• US Classifications

  • 356 - Optics: measuring and testing