From this webpage:

In 1879, after testing more that 1600 materials for the right filament, including coconut fiber, fishing line, and even hairs from a friend's beard, Edison and his workers finally figured out what to use for the filament--carbonized bamboo.

I'm a little surprised it took Edison that many tries to get it right. 1600 different materials is quite a lot. Did Edison go through about 1600 tests? Are there any first-hand accounts that prove it?

(Note: the page does say that Edison took detailed notes (40,000 pages, apparently), so I would think he would have a detailed chronology and record of the tests there.)

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    Note that he had about 40 people working for him at that time, that would be 40 materials per person (also note that material here denotes configuration, that could mean 40 times copper in different lengths, thicknesses etc.) – PlasmaHH Nov 19 '14 at 13:08
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    There are indeed first hand account, but unfortunately they are not all searchable. See The Thomas A. Edison Papers. The book "The Papers of Thomas A. Edison: Electrifying New York and Abroad, April 1881-March 1883" (page 235) writes that: "He noted in September 1881 that 1,600 to 1,700 raw fibers were needed to produce 1,000 finished lamps." But it is no entirely clear whether this is referring to the – iantresman Nov 30 '14 at 23:32
up vote 15 down vote accepted

Someone has investigated the authenticity of the anecdote that this number is often a part of.

Another source that notes that Edison did test 1,600 materials is a 1910 biography titled, Edison, his Life and Inventions by a Frank Lewis Dyer, "General Counsel for The Edison Laboratory And Allied Interests". The foreword notes that much of the information in the book has been compiled based on Edison's own written and oral statements as well as contributions from his associates. As Edison died only in 1931, this book was actually written during his lifetime.

From page 605:

The "try everything" spirit of Edison's method is well illustrated in this early period by a series of about sixteen hundred resistance tests of various ores, minerals, earths, etc., occupying over fifty pages of one of the note-books relating to the metallic filament for his lamps.

So, a contemporary employee/associate of Edison confirms that 1600 various materials were tested for his light bulb and this is based on a notebook used to record the experiments at the time.

IOW, the claim is true.

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    Frank Dyer's book is freely available on Gutenberg. – user7920 Mar 27 '15 at 21:27
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    I'll accept this answer because it specifically addresses the claim, even though Dave's answer is extremely well researched. – HDE 226868 Mar 30 '15 at 16:34

Form Thomas Edison's May 14th, 1904 article in Scientific American Supplement No. 1480, page 23711:

I soon ascertained why and started a man off for Japan on a bamboo hunt. Before I got through I had tested no fewer than 6,000 vegetable growths, and had ransacked the world for the most suitable bamboo. The use of bamboo was maintained for many years...

The same passage also appears in the 1904 Electrical World and Engineer volume 43, page 432.

So at least you have a clear 111 year old statement from a first hand witness, Edison himself, that he did test more than 1,600 materials.

A really great resource to address your question is "The life and inventions of Thomas Alva Edision" 1894 by William Kennedy-Laurie Dickson and Antonia Dickson.

This book has extreme details including many photographs and even a microscopic photograph of the worldwide hunt for fibers. As summarized on page 226:

no fewer than 80 varieties of bamboo and 3,000 kinds of vegetable fibre were tested

If you see the photographs in this book and read the quotes from Mr. Racilton who went to Ceylon and India to find fibers for Edison, I think you will be convinced.

  • This is helpful, but it only establishes Edison's investigations into bamboo. The claim involves over 1600 unrelated materials. – HDE 226868 Mar 27 '15 at 20:44
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    Nobody is claiming he tested 1600 "unrelated" materials. The assertion quoted in your question is open to many of the materials being highly related, different species of bamboo, the same bamboo processed in different ways, etc. Here he is stating he tested 6,000 plant samples, not necessarily bamboo. – DavePhD Mar 27 '15 at 20:51
  • Fishing line and beard hair are not plant samples. I mistyped above ("bamboo" should have been "plants"). – HDE 226868 Mar 27 '15 at 20:52
  • At that time, fishing line probably was plant material. Beard hair is not plant material. So at least 1 of the 1600 is claimed not to be plant material. 1599 could have been plant material. – DavePhD Mar 27 '15 at 20:55
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    @HDE226868 I added another source of information to the answer. – DavePhD Mar 30 '15 at 15:58

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