October 21 is the Day of AKARI in Japan
The “Day of AKARI(Lighting)” in Japan is celebrated with the co-ordination of four associations every year on October 21 from 1981 and this is the 26th year. The four associations are: Japan Electric Lamp Manufacturers Association,Japan Luminaries Association, Japan Electric Association and Popularization Society of Illuminating Engineering Institute of Japan. Thomas Edison invented the practical incandescent lamp for the first time in the world on October 21, 1879. Edison’s great works were praised, creation of the affluent society by improvement in lighting culture was wished, and the “Day of Lighting” on October 21 was enacted. Edison’s greatest contribution to the problem of electric light was in filament design. He tried over 6,000 alternative filament materials over two years, and spent $40,000 conducting more than 1,200 experiments.
Finally, Edison tried carbonized cotton sewing machine thread. On Sunday evening, October 19, 1879, Edison and his assistants powered up his cotton filament and took turns watching it around the clock. More than 40 hours later it was still glowing and Edison knew he had the problem solved.