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This is an exact replica of Edison’s first successful lamp.

"The one depicted in this photo was probably constructed by Francis Jehl, one of Edison’s pioneer assistants.  And the one shown in the sample exercise you may have completed was constructed in 1929 to commemorate the 50th Anniversary of Edison’s first successful electric lamp.  This is what the first successful practical lamp made by Thomas Edison and his team in Menlo Park, NJ in October of 1879 looked like.  This example of the bulb was reproduced to the exact specifications of the original made in October of 1879.  It consists of a carbonized thread for the filament which was attached to the inner leads by means of both carbon paste and copper clamps and screws, all mounted in a hand blown glass bulb whose air was pumped out by means of a Sprengel mercury pump (which required about 5 hours to do).  Note that no base of any kind was actually used to mount the bulb in the original successful lighting experiment in October of 1879.  This particular so-called base was not conceived of until shortly after Edison’s first successful light bulb experiment that occurred in October of 1879.  Edison and his team designed this base to mount Edison’s first commercial light bulbs, which he sold in late 1879 to early 1880 before bulbs were fitted with threaded bases.

In the early days of electric lighting and for many years afterward, “light bulbs” were commonly referred to as “lamps” or “electric lamps,” a term no doubt derived from the term “oil lamps,” which the incandescent lamps ultimately replaced.  Notice that the bulb of this lamp does not conform to the typical pear shape of many other household light bulbs.  The bulb is quite spherical or globular in shape and is connected to a long, straight neck with terminal wires hanging out.  With a piece of carbonized cotton sewing thread used as the filament (the thread reportedly supplied by Thomas Edison’s wife from her sewing kit), the original bulb was said to have burned for over 40 hours as Edison and his crew watched and waited during that whole time (the so called “Death Watch”).  However, notes kept by members of Edison’s team reveal that Edison’s first successful light bulb may have burned for only 13 ½ or 14 ½ hours and that the 40-hour “Death Watch” took place a few days after these two demonstrations, if it actually did occur.  Nevertheless, after the filament finally burned out, the bulb was broken apart so that the individual parts, especially the filament, could be analyzed and thus was destroyed during this process.  No pieces or photos of the original bulb have ever been found."

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