国立アメリカ歴史博物館のインスタグラム(amhistorymuseum) - 1月28日 00時57分

Today in 1880: Thomas Edison receives a patent for the incandescent lamp. The hardest part was picking a material for the filament. He tested 1,600 materials, including beard hair. Do you know what eventually was found to work best?

[BIHAKUEN]UVシールド(UVShield)

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