Henry Woodward and Mathew Evans Lamp
There are claims in the technical literature, as well as on the internet, that different individuals invented the electric incandescent lamp before the generally-accepted work of Thomas Edison. One might conclude that national pride is involved but the present writer concludes that such assumptions probably have been made because of a lack of understanding of the subject. A few examples of individuals will be given.

If one types the name "James Bowman Lindsay" in a search engine, such as Google, several web pages will be found that describe, in somewhat sketchy terms, a lamp Lindsay developed in his hometown in Scotland in 1835. A writeup on Lindsay can be found on this website. A second name, that of Henry Goebel, also can be mentioned. Much patent litigation resulted because of Goebel's claims for developments that started as early as 1854. A writeup about Goebel can also be found on this website. This writer concludes that neither investigator could rightly claim the practical design developed by Edison. A third case that involves two Canadians will be considered here briefly.

So—what precisely did Edison claim in his basic filament and lamp patents? In order to avoid the mistake of assuming that someone invented the practical incandescent lamp before Thomas Edison did, it is necessary to state exactly what the Edison claims were. This can be answered easily by quoting from Howell and Schroeder5:

"That is what Edison invented: a lamp with a high resistance filament of carbon in a vacuum contained in a glass container closed at all points by fusion of the glass and having platinum wires imbedded in the glass to carry current through the glass to the filament. And this was the first incandescent lamp which was suitable for the system of general multiple distribution which solved the problem of the 'sub-division of the electric light.'"
Two names of persons who lived in Toronto, Canada can also be found on the internet and the claim is that they, also, preceded Edison in his development. Their story is given below from an article that appeared in Electrical World and Engineer4.

"The story of the invention of the incandescent lamp by the Canadian, Woodward, has recently again been brought forward. A Canadian correspondent writes that some interesting historical data has recently been supplied by Mr. Wright, of the Toronto Electric Light Company, and Mr. Patriarche, of the Electric Maintenance Company, of Toronto, Ont., relative to the original discovery of the principle of incandescent electric lighting. This discovery is claimed to have been made in the City of Toronto, and patented in Canada and the United States prior to the time when a patent was granted to Edison; and, moreover, that the patent for the Canadian discovery was purchased by Mr. Edison at the time when he was making his original investigations and before he obtained his patent. The details of the story are that Henry Woodward, a medical student, and Matthew Evans, a hotelkeeper, of Toronto, were neighbors and frequently experimented together with a large Smee battery and induction coil, of which Woodward was the possessor. While seated at dusk one evening watching the buzzer of the induction coil, the light of the spark at the contact post attracted their attention. It impressed them with the idea that if they could confine the spark in a globe a marvelous invention would be the result. From this beginning, in the early part of 1873, Woodward and Evans worked to perfect the idea, and on August 3, 1874, they were granted a Canadian patent. The first incandescent lamp was 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. After the invention had been tested a company was formed for the supply of electric lights to the public. Some of the original stockholders had invested capital in the enterprise before having seen the light and when asked to put up more money on the same conditions, declined. Woodward became displeased and left for Europe, and is now said to be residing in London, England. Evans died in Toronto last year. The comment on this story is that 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."

The drawings from Woodward's 1876 United States patent, which are shown above, are almost exactly the same as those that appeared in Woodward and Evan's 1874 Canadian patent. The carbon burner (labelled "B" — Fig. 1, for example) can be seen to differ widely from Edison's filament, which is a most important feature of a practical lamp.

As the 1900 article mentioned4, earlier workers had advanced to the same or higher degree in their work as did Woodward and Evans. To name a few: J. B. A. M. Jobard in 1838, C. de Changy in 1856, John Wellington Starr in 1845 and Joseph Swan in 1860. All these workers contributed, in one way or another, to the eventual development of the incandescent lamp, but it was Thomas Alva Edison who put the necessary ingredients together to make the lamp and system practical.

References
1) Henry Woodward and Mathew Evans, Electric Light, The Canadian Patent Office Record, Aug 1874, pg 75, No. 3738.
2) H. Woodward, Electric Light, U.S. Patent No. 181,613, Aug 29, 1876.
3) Canadian Electrical News, Feb 1900.
4) "Invention of the Incandescent Lamp", Electrical World and Engineer, Vol 35, No 15, Apr 14, 1900, pg 540.
5) History of the Incandescent Lamp, John W. Howell and Henry Schroeder, The Maqua Company, Publishers, Schenectady, NY, 1927, pg 61.
6) http://www.bouletfermat.com/danny/light_bulb_patent.html