One of Edison's key associates was a mathematician/physicist by the name of Francis Robbins Upton. Upton was born in Peabody, Massachusetts on 26 July 1852. He attended Phillips Academy at Andover, Massachusetts, and received a Bachelor of Science degree in 1877 at Bowdoin College in Brunswick, Maine. He attended Princeton University and then studied at the Berlin University for one year under Helmholtz. He went to work for Edison in November, 1878. Upton passed away in Orange, New Jersey on 10 Mar 1921.
Some of Upton's activities and achievements were described in The Story of Electricity4:
"But his usefulness was not circumscribed by any narrow definition of grade; on the contrary, he ably conducted much of the important early work of the Edison laboratories. There developed, for instance, his mathematical analysis of the multiple arc feeder and three wire system of electric lighting. He performed many important experiments bearing upon the incandescent carbon filament; lighting a No. 2 high resistance lamp beside a No. 1 and observing that No. 1 did not flicker; being the first to raise carbon filaments to a higher point of incandescence when they were being exhausted than they would be subjected to at normal candle power. He designed the present Edison base on incandescent lamps, sending the gauges out to the world; he took charge of Edison's search for fibres; he was commissioned to buy the first parcel of land for the Edison Illuminating Co. of Boston."References and Bibliography
A note to the Editor of Scribner's Monthly from Thomas Edison that appeared at the beginning of Upton's article titled "Edison's Electric Light," Feb 1880, pp 531-544.