Question

"The button you touch outside is electric; it opens the door and at the same time rings the bell in my study, thus informing me of a visitor. When the visitor steps across the threshold he treads, whether he will or no, on another apparatus, which closes the door behind him and rings another bell in my page’s room, who immediately comes to me for orders." what was the invention

Answer 1

This story represents the Automatic Door, invented in 1954.