These letters, which cover the years 1880-1888, are addressed to Thomas Logan, supervisor of the machine shop at the Menlo Park laboratory. The correspondents include Edison, writing from the New York office of the Edison Electric Light Co., and Charles L. Clarke, chief engineer of the company. Many of the items contain instructions about steam dynamo design, construction, and testing; a few were annotated by Francis Jehl during the 1930s. There is also an undated drawing by Edison of copper tubes enclosed in an alloy cylinder, along with an 1888 letter from John Kruesi describing the manufacture of telephone chalks.
[X001M6AA] Technical Note, 1878-1887 1878-1887
[X001M6AA1], Letter from Thomas Alva Edison to Thomas Logan, 1880 1880-00-00
[X001M6AB], Letter from Charles Lorenzo Clarke to Thomas Logan, February 16th, 1881 1881-02-16
[X001M6AC], Letter from Thomas Alva Edison to Thomas Logan, March 1st, 1881 1881-03-01
[X001M6AD], Letter from Thomas Alva Edison to Thomas Logan, March 5th, 1881 1881-03-05
[X001M6AE], Letter from Thomas Alva Edison to Thomas Logan, 1881 1881-00-00
[X001M6AF] Letter, 1881-1882 1881-1882
[X001M6AG], Letter from Thomas Alva Edison to Thomas Logan, 1882 1882-00-00
[X001M6AH], Letter from Charles Lorenzo Clarke to Thomas Logan, 1882 1882-00-00
[X001M6AI], Letter from John Kruesi to Thomas Logan, January 12th, 1888 1888-01-12