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Talk:Henry Woodward (inventor)

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It was in Mental_Floss's new issue

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It said Henry Woodward and Matthew Evans [1]invented the light-in-the-bulb form and they always check their facts before publishing each magazine... Mentalfloss.com Go to Barnes and Nobles etc and turn to page 41 of the july august 2005 issue... It's under Who Really Invented the Light Bulb (Hint: It Wasn't Edison)

Does "Mental Floss" cite any documents other than the patent? Or are they just parroting Wikipedia and the other unreferenced claims that the 2 Canadians were the "true inventors (ignoring the earlier work of Swan and Sawyer among others)? Do they have any evidence that Edison bought the patent? The usual story is that he "bought" it in 1875, but scholarly histories do not show him working on electric lights until several years later, and patent law does not work in any way remotely like "buy a patent in 1875, then patent the same thing in 1880 and take credit for it" as implied. In 1894 rival manufacturers were literally counting down the days until Edison's patent expired so they could legally make evacuated light bulbs with carbon filaments. His patent definitely did not involve filling the bulb with nitrogen or any other inert gas, because he found that that cooled a carbon filament excessively and caused low brightness and early failure. The later tungsten filaments were coiled into a smaller area so the cooling effect was not a problem when inert gas was added, as in 20th century bulbs. Edison 21:32, 15 May 2007 (UTC)[reply]

References

  1. ^ Insert footnote text here

Anonymous

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The US patent Woodward patent # is 181,613, granted August 29 1876. I believe the Edison patent # is 214,636 granted March 25 1879. Why the Edison patent was granted in the light of the Woodward patent is a mystery to me. ME too

The Edison patent was ultimately upheld by the U.S. Supreme Court. His contribution to the evolution of incandescent light technology was the use of a carbon filament of very small cross section, so that the resistance was high and it was possible to use it commercially at a distance from the generator, and an extremely high vacuum, and a one piece bulb with the leads sealed to prevent air leaking in. His bulb produced more light than a gas jet, operated for a fraction of the cost, and could be powered by the central generating station. It also had a lifetime of several hundred hours. Previous incandescent lamps had a very short lifetime, and/or gave off too little light, and drew extremely high current, making them impractical. Patenting an impractical lightbulb, which is an improvement over someone else's patent of years before for an earlier bulb that did not work in any practical sense, does not make these two the "inverntors' of the electric light, any more than Sawyer's patent in the 1840's or Humphrey Davy's demonstration of making a platinum filament glow in 1802. There are 2 sources provided in this article: One is some professors opinion from 1984, apparently not published in a refereed journal, and the other is an old engineering journal at a site which presently does not open.Given the weight of scholarly opinion on the other side of the balance , far better evidence in needed that their light worked, producing a useful amount of light for a long enough time at an econi=omic enough current draw, and the other claim that Thomas Edison bought their patent and called it his invention. Most earlier bulbs used a larger cylinder of carbon which cannot properly be called a "filament" and which drew excessive current, so that it could only be heated up momentarily, to impress investors. With a carbob filament of tiny cross section, nitrogen prevented it staying hot enough to work and reduced the lifetime by the air currents from convection. Edison 06:26, 28 April 2007 (UTC)[reply]

Factual Acuracy

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I wonder if this information/source is cretitable? I have searched the web and many other resources and I can't seem to find much about "henry woodward." It would help if the person who wrote this article (or anyone else) could verify this information (citations?). I know this is wikipedia and there is no garentee of accurate information, but i think if an article cannot be confirmed, it should be deleted. toe cheese grater?? nose hair/salad fork??


uh, also... check this out... http://inventors.about.com/library/inventors/bllight.htm

The Canadian Broadcasting Corporation supports the claim. -- Zanimum 19:42, 12 September 2006 (UTC)[reply]


The "inventors.about" website is of the same quality as Wikipedia, and is not a reliable source to satisfy WP:A. Ditto fro some unspecified claim by CBC. Find scholarly books from reputable publishers which provide footnotes showing where the authors got their information. Find court cases where the final ruling was for the priority of the 2 Canadians. You may look a while. Some popular books which have appeared recently sound like they cribbed from Wikipedia, so it becomes circular. Edison 06:29, 28 April 2007 (UTC)[reply]

Is there a conflict?

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Patent 181,613 was indeed granted to "H. Woodward" of Toronto. It is for a lamp consisting of a lump of carbon, in an evacuated globe, heated by the passage of electric current. The concept described in that patent does not seem to me (retired electronic engineer) to be workable.

There is a gap in the history. I have heard of Edison and an electric lamp using a filament of carbonized organic material (silk of cotton). One of these orignial carbon filament lamps may still be in operation. I did not track down a patent on this.

Patent 214,636 is for a filament of precious metal and an intricate current regulation system, to keep the filament hot enough to illuminate but not hot enough to melt. The temperature problem was solved with the introduction of tungsten, which is self-regulating. Heated to the familiar intense white heat, its electrical resistance is about ten times the cold resistance.

The claim for Edison was for the first __practical__ electric light (emphasis added) which seems to be a valid assertion.

US patents may be found in the US Patent and Trademark Office site, http://patft.uspto.gov/netahtml/srchnum.htm for any and all. Old patents are delivered as images, and require Apple Quick Time.

Every invention has a horde of poeple who come along later and seek to take credit by pointing to some early impractical attempt. That is why Wikipedia requires reliable sources per WP:A. The mass of scholarly research shows that there were dozens of failed attempts to make an incandescent lamp, from Davy in 1802 to Edison's success in 1879. The scholarly judgment is that his was the first practical incandescent electric lamp. If the earlier ones had worked, then the leading scientists of the late 1870's such as William Thompson would not have derided him as being on a fool's errand for trying yet again to make an incandescent lamp work. Swan and Edison were working pretty much in parallel, but Swan used an excessively thick filament and had not developed or obtained an adequate vsacuum pump. See "Empires of Light, Jill Jonnes, Randon House, 2003, which is a recent very readable scholarly treatment, which on p55 says "For forty years, scientists and inventors- American and English, French, Russian Belgian- had been largely frustrated in their efforts to create a practical indoor electric light, some kind of enclosed glass globe that could safely and brightly glow." Then Edison in September 1878 prematurely announced he had solved the problem, using a platinum filament with a regulator to prevent it melting. He and his crew worked tirelessly until they got a carbon thread filament to glow brightly for an extended period in Oct. 1879. He demonstrated a number of these carbon filament bulbs publicly in December 1879. Through more tireless experimentation they invented the carbonized bamboo filament bulb in 1880. There is no indication that any patent of Woodward played any role in these developments. In September 1882 Edison's Pearl Street generating station in New York, with efficient generators of his invention, powered up about 400 bulbs, with 2000 more in ensuing months. All by the Edison patent. Not the Woodward patent. "Illumination Engineering," by Joseph P. Murdoch, Macmillan, 1985 says , p4, "From De la Rue's lamp in 1820 until Edison lit his first successful lamp in 1879, many people worked on incandescent lamp development. However, the lamps they created did not prove practical, largely because of unreliability, short life, and excessive operating expense." He says all these predecessor lamps "used thick filaments, either of platinum or carbon, which had low electrical resistance and required large currents to heat themto incandescence." Nothing about Woodward or his cohort. "Fleet Fire" by L. J. Davis, Arcade Publishing, 2003 says p22 that electric light experimenters from Davy onward had tried carbon filaments unsuccessfully. Edison 06:57, 28 April 2007 (UTC)[reply]


reference #1 is a broken link. —Preceding unsigned comment added by 131.162.156.129 (talk) 23:37, 16 April 2009 (UTC)[reply]

File:Light bulb patent.jpg Nominated for Deletion

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