Joe; This is a gag, isn't it? My grandma's house was full of these 1910-era "emergency shutoff switches". These switches seem to be making a comeback in new houses built in a victorian style. These devices were nearly indestructible. I have several of these in my collection.
I will have to go back to that location soon to check, but it probably was for the "AC Electric Service" or maybe the heating system, which may be a oil burner.