One day, Edison was sitting in his laboratory absent-mindedly rolling a piece of compressed carbon between his fingers. He began carbonizing materials to be used for the filament. He tested the carbonized filaments of every plant imaginable, including baywood, boxwood, hickory, cedar, flax, and bamboo. He even contacted biologists who sent him plant fibers from places in the tropics. Edison acknowledged that the work was tedious and very demanding, especially on his workers helping with the experiments.

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