[NM017AAT], Technical Note, Thomas Alva Edison, October 9th, 1882



"Patent lamp consisting of two or more separate filaments of flexibile carbon cut from the same material and carbonized together so as to ensure same quantity as to resistance & economy to permit the two or more filaments to be worked in series." [with drawing]. Other drawings "mention 2 or more filaments may be put in this way worked in M arc or series" Discusses & illustrates manufacture of such a lamp. Image 75 begins a separate patent for "gelatinizing vegetable fiber by hydroflouric acid." Illust of "filament is brought up to dull red in the hydrocarbon oil bisulphie carbon or other liquid whose gas is not decomposable at a low red heat. This permits of as [enlarging?] propbly if a carbon filament is perfect before putting in lamp the filament is not allowed to reach a temperature sufficient to decompose the tlightest the gas or deposit anything upon the carbon" Can lower resistance by soaking in sugar solution, then immersed in bath & brought to red heat. Then drawing and text for another idea, to fill a tube with a filament packed around with finely "powdered zirconia, magnesia, alumina, lime or othe roxide or even mtalic boron & then exhausting heating the glass by extraneous source heat while exhausting when exhaused the carbon is gradually brought to incandescence & then brought up to such a tem as to melt the oxide in proximity to the carbon." Then sketches to prevent carbon carrying: "carbon positive, Earth negative or zero. Hence glass so current makes glass positive changes it & carrying is prevented." For bringing glass globe to same or nearly same potential as filament. [[see US pat 273,486] Then notes for a double globe lamp







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[NM017AAT], Technical Note, Thomas Alva Edison, October 9th, 1882

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

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