Henry Woodward was a

Canadian Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...

inventor and a major pioneer in the development of the

incandescent lamp An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated until it glows. The filament is enclosed in a glass bulb with a vacuum or inert gas to protect the filament from oxida ...

. He was born in 1832.Library and Archives Canad
Incredible Inventions: Light Bulb
www.collectionscanada.ca On July 24, 1874, Woodward and his partner, Mathew Evans, a hotel keeper, filed a Canadian

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A ...

application on an electric

light bulb An electric light, lamp, or light bulb is an electrical component that produces light. It is the most common form of artificial lighting. Lamps usually have a base made of ceramic, metal, glass, or plastic, which secures the lamp in the soc ...

. It was granted on August 3, 1874, as Canadian patent number 3,738.“Canadian Patents: List of patents granted August 3 to August 13, 1874”, Scientific American, Vol XXXI – No. 11, September 12, 1874 p 172.
/ref> Woodward was a medical student at the time. Their light bulb comprised a glass tube with a large piece of carbon connected to two wires. They filled the tube with inert

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

to get a longer burn life in the filament. Their light bulb was fully effective and sufficiently promising; they sold their to

Thomas Edison Thomas Alva Edison (February 11, 1847October 18, 1931) was an American inventor and businessman. He developed many devices in fields such as electric power generation, mass communication, sound recording, and motion pictures. These inventi ...

and due to this Edison is now known for the invention of the light bulb. Thomas Edison obtained an exclusive license to the Canadian patent. Thomas Edison developed his own design of incandescent lamp with a high resistance thin filament of carbon in a high vacuum contained in a tightly sealed glass bulb which had a sufficiently long service life to be commercially practical. The relationship of the Woodward/Evans work on the incandescent bulb to that of others, including Edison, on electric light is explained in the following passage of an article in a 1900 issue of ''Electrical World and Engineer'' as follows:

"The first incandescent lamp eveloped by Woodward and Evanswas constructed at Morrison's brass foundry in Toronto and was a very crude affair. It consisted of a water gauge glass with a piece of carbon, filed by hand and drilled at each end, for the electrodes, and hermetically sealed at both ends, having a petcock at one end with a brass tube to exhaust the air. Woodward made the mistake of filling the tube or globe of this lamp with nitrogen after having exhausted the air. Prof. Elihu Thomson is quoted as having said that had he stopped when he had the tube exhausted he would have had the honor of being the inventor of the incandescent light as used for commercial purposes... the principle of the incandescent lamp dates several decades before the Woodward experiments, and that King, Chanzy, Farmer and others in the twenty years preceding 1860 made and used incandescent lamps much superior to the very imperfect one upon which Woodward's claims are based. Moreover, the Edison claims, as sustained in the courts, were not on the discovery of the principles of the incandescent lamp but on a definite combination of parts—all well known—which resulted in the production of a practical form of the incandescent lamp."

Woodward & Evans did not have enough money to develop their invention, so they sold the rights to U.S. Patent 181,613 to Thomas Edison. The drawings from Woodward's 1876 United States patent are almost identical to those that appeared in Woodward and Evans' 1874 Canadian patent. The carbon burner, a "most important feature of a practical lamp" differs widely from Edison's filament. Several earlier inventors working on the light bulb had progressed as far in their work as Woodward and Evans:

Marcellin Jobard Jean-Baptiste-Ambroise-Marcellin Jobard (17 May 1792 – 27 October 1861) was a Belgian lithographer, photographer and inventor of French origin. Founder of the first significant Belgian lithographic establishment, first photographer in Belgium ...

in 1838, C. de Changy in 1856, John Wellington Starr in 1845 and

Joseph Swan Sir Joseph Wilson Swan FRS (31 October 1828 – 27 May 1914) was an English physicist, chemist, and inventor. He is known as an independent early developer of a successful incandescent light bulb, and is the person responsible for develop ...

in 1860. Each contributed to the development of the incandescent lamp, but it was Edison who assembled the necessary components to make the first practical electric light bulb. What is known about Woodward's discovery is that it was patented in Canada and the United States prior to a patent being granted to Edison and it is known that the patent for the Canadian discovery was purchased by Edison when he was making his original investigations and before he obtained his patent.

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Ricketts, Bruce

{{DEFAULTSORT:Woodward, Henry 19th-century Canadian inventors Canadian electrical engineers People from Old Toronto Year of death missing 1832 births

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