These documents consist of two undated items by Edison from the Autograph Letter Collection, along with a 1907 letter by journalist George Iles from the Isles Papers (MS413). The first item is a letter to Franklin H. Badger, superintendent of the Montreal Fire Alarm System, describing improvements in Edison's carbon telephone transmitter. The letter possibly dates from September 1877, when Edison appointed Badger sole agent for his telephone in Canada. Also included is a note to laboratory chemist Otto Groethe, possibly written during the period 1906-1910, concerning experiments on electrolytic reactions in alkaline storage batteries. The April 1907 letter from Iles asks Edison's permission to reprint an article from the Electrical World relating to the invention of the incandescent lamp.
[X312A], Letter from Thomas Alva Edison to Franklin Hodgkins Badger, September 26th, 1877 1877-09-26
[X312B] Letter, 1906-1910 1906-1910
[X312C], Letter from George Iles to Thomas Alva Edison, April 29th, 1907 1907-04-29