Despite Edison's controversy in scientific history, a lot of Japanese people admire him for he shares a history with Japan. As he worked on improving the light bulb's lifespan, he experimented with different materials until one of his workers, William H. Moore, sent him bamboo samples growing near the Iwashimizu Hachiman Shrine in Kyoto.
It’s not clear whether Edison asked Moore to send him that particular species of bamboo, or Moore sent them to Edison of his own volition. In any case, Edison discovered that carbonized bamboo made excellent lamp filaments.
To make these filaments, pieces of a single bamboo plant was sliced lengthwise into extremely fine strips, and bent to their desired hairpin or looped shapes in order to fit into the bulb.
They were then covered with powdered carbon and heated inside a furnace at an extremely high temperature for several hours before allowing them to cool. During this process, the bamboo strips turns from its initial cellulose structure to a pure carbon structure, ready to be mounted in the glass bulbs.
The carbonized bamboo filament weren't brighter but they lasted significantly longer than any existing filament at the time with some burning for over 1,200 hours. Until 1904, carbon filament was used in manufacturing incandescent lamps after which the tungsten filament was discovered. Edison's company, General Electric, then switched to tungsten.
The people of Iwashimizu Hachimangu then built a monument in honor of him three years after he died.
(Image credit: Katie/Flickr)