Items

• [E1518CCD], Letter from Thomas Alva Edison to Heyden Chemical Works, March 15th, 1915
  1915-03-15
• [E1518DFX], Letter from Thomas Alva Edison to Heyden Chemical Works, April 27th, 1915
  1915-04-27
• [E1518ECI], Letter from Thomas Alva Edison to Heyden Chemical Works, May 20th, 1915
  1915-05-20
• [E1616IBL], Letter from Thomas Alva Edison to Heyden Chemical Works, September 27th, 1916
  1916-09-27
• [LB110460], Letter from Thomas Alva Edison to Heyden Chemical Works, February 26th, 1916
  1916-02-26
• [LB112443], Letter from Thomas Alva Edison to Heyden Chemical Works, June 5th, 1916
  1916-06-05
• [LB112487], Letter from Thomas Alva Edison to Heyden Chemical Works, June 9th, 1916
  1916-06-09