The Story of Thomas Edison and the Electric Light

Originally published in 1911 as part of the author’s larger “Historic Inventions,” this Kindle edition, equivalent in length to a physical book of approximately 24 pages, describes, in simple language, the life and work of Thomas Edison, especially his invention of the light bulb.

Sample passage:
His experiments had already resulted in the production of an almost absolute vacuum, only one-millionth part of an atmosphere being left in the tube. Such a vacuum had never been obtained before. With his assistant, Charles Bachelor, he put a thread of the lampblack and tar in a bulb, exhausted the air, and turned on the current. There was an intense glow of light; but it did not last, the carbon soon burned out. Therefore he started to study the reason why the carbon had failed to withstand the electric current. His conclusion was that it was impossible to get the air out of the lampblack. Besides that, the thread became so brittle that the slightest shock to the lamp broke it. But he felt certain now that a carbon filament, made of something other than tar and lampblack, was what he wanted.

He next sent a boy to buy a reel of cotton, and told his assistants he was going to see what a carbonized thread would do. They looked doubtful, but began the experiment. A short piece of the thread was bent in the form of a hairpin, laid in a nickel mold and securely clamped, and then put in a muffle furnace, where it was kept for five hours. Then it was taken out and allowed to cool. The mold was opened and the carbonized thread removed. It instantly broke. Another thread was put through the same process. As soon as it was taken from the mold it broke. Then a battle began that lasted for two days and two nights, the object of which was to get a carbonized thread that would not break. Edison wanted that thread because it contained no air, and might stand a greater current than the lampblack. Finally they took from the mold an unbroken thread, but as they tried to fasten it to the conducting wire it broke into pieces. Only on the night of the third day of their work, in all which time they had taken no rest, did they get a thread safely into the lamp, exhaust the air, and turn on the current. A clear, soft light resulted, and they knew that they had solved the problem of the incandescent light.