[N111039], Technical Note, Thomas Alva Edison, Francis Robbins Upton, October 6th, 1880



Entire notebook is test of 100 lamps at high voltage. Each lamp seems to have its own resistance circuit or coil. Want them at 48 c.p. Continuing test notes; which lamps failed when, where (marked on sketches of carbons). Many, many lamps; occasional lists of lamps in which blue or other phosphorescence is observed. FR 761: "I notice that the extra bad vacuum lamps have their carbons very much bent over these don't give more thatn 4 or 5 candles (there's only two) There is not one carbon in this whole except the above two that is not straight enough & the great majority are quite straight." Remarks on doubts about the pumps; observation of carbon vapor adhering to glass in a specific spot. FR 785 lamps seem like 30 candles instead of the 48 they're supposed to be. FR 797 "at 2:30 am 6 hours & 20 minutes from start 33 lamps still going out of 97 that started." Fr 808; at 178 volts #91 "has fallen from 48 candles at 2 o'clock to 39 candles at 3:56 am. Observing that air comes out & reduces economy even after it has been at 48." Summary tables and averages: volts, 300 candles/HP.... Fr 816 numerical breakdown of where carbons broke. Fr 827 "summary lot 1" FR 832 BEGINS notes on carbonization in muffle. Fr 837: Upton's "Results." Lamps had poor vac; longest-lasting were those requiring least EMF to bring to 48 candles.







Folder Set



[N111039], Technical Note, Thomas Alva Edison, Francis Robbins Upton, October 6th, 1880

Microfilm ID



Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University