. Electrical world. FIG. I.—FIRST PHOTOGRAPH TAKEN BY INCANDESCENT LIGHT. (Reproduction of Photograph taken by Mr. Edison at his Menlo[ark Laboratory at midnight about Dec. 20, 1879, by the light of threeof his first electric lamps. The portrait is that of .Mr. CharlesBatchelor.) vacua. It occurred to me that perhaps a filament of carbon couldbe made to stand in the sealed glass vessels or bulbs, which we wereusing, exhausted to a high vacuum. Separate lamps were madein this way independent of the air pump, and in October, 1879, ^^^made lamps of paper carbon, and with carbons of common sewingt
. Electrical world. FIG. I.—FIRST PHOTOGRAPH TAKEN BY INCANDESCENT LIGHT. (Reproduction of Photograph taken by Mr. Edison at his Menlo[ark Laboratory at midnight about Dec. 20, 1879, by the light of threeof his first electric lamps. The portrait is that of .Mr. CharlesBatchelor.) vacua. It occurred to me that perhaps a filament of carbon couldbe made to stand in the sealed glass vessels or bulbs, which we wereusing, exhausted to a high vacuum. Separate lamps were madein this way independent of the air pump, and in October, 1879, ^^^made lamps of paper carbon, and with carbons of common sewingthread, placed in a receiver or bulb made entirely of glass, with theleading-in wires sealed in by fusion. The whole thing was exhaustedby the Sprengel pump to nearly one-millionth of an filaments of carbon, although naturally quite fragile owing totheir length and small mass, had a smaller radiating surface and. FIG. 2.—VIEW OF EDISON LABORATORY, MENLO PARK, N. J. (Showing buildings and outdoor circuits lighted by incandescentlumps, December, 1879.) higher resistance than we had dared hope. We had virtually reachedthe position and condition where the carbons were stable. In otherwords, the incandescent lamp as we still know it to-day, in essen-tially all its particulars unchanged, had been born. We began immediately to make vacuum pumps and to producethese paper filament lamps on them. During that November wemade perhaps as many as 100 of such lamps, and the same monthsaw us plunged deep in experiments and inventions on dynamos,regulators, meters, circuits, all just as necessary to the successof the art as the little lamp itself. Some of those paper filamentlamps had a remarkably long life. Each yielded from 12 to 16 cpand they were burned on chandeliers until they gave out. Theaverage life was about 300 hours. One of them lasted 940 hoursand another hours, so that commercial su
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectelectri, bookyear1883
