Thomas Edison did not give up on his first efforts to find an effective filament for the incandescent lamp. He did countless experiments with countless materials. As each failed, he would toss it out the window. The pile reached the second story of his house. Eventually, he sent men into many different countries such as, Japan, South America, Asia, Jamaica, Ceylon, and Burma in search fibers and grasses to be tested in his lab. One weary day, on October 21, 1879, after 13 months of repeated failures, he succeeded in his search for a filament that would stand the stress of electric current. This is how it happened. Casually picking up a bit of lampblack, he mixed it with tar and rolled it into a thin thread. Then the thought occurred to him, “Why not try a carbonized cotton fiber? For five hours he worked, but each time it broke before he could remove the mold. Two spools of thread were used. At last a perfect strand emerged, only to be ruined while being placed in a glass tube. However, Edison refused to be defeated. He worked non-stop for two days and nights without sleep. Finally he managed to slip one of the carbonized threads into the sealed glass bulb. When he turned on the current, he beheld a sight that he had worked so long for, the bulb burned and provided light.