Your double dose of awesome for today: a photo of Mark Twain visiting Nikola Tesla’s laboratory in 1894. The image is a ten-minute (!) time-lapse photograph taken for an article in the Century, and in it Twain illuminates one of Tesla’s wireless light globes:

Refining his theory on wireless communication, the inventor realized that electrical energy could be transmitted in two distinctly different ways, one as radiation through the air, and the other as conduction through the ground. Today this difference corresponds to FM and AM radio.

…Tesla began to realize that he could design vacuum tubes which would respond only when a precise combination of two or more circuits were being triggered. One of the lamps held by Twain was illuminated in this manner, its dual circuit triggered by a correspopnding dual circuit created by two cables laid around the room.