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


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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


October 6, 1880