Historic American Buildings Survey (HABS)

[L Verge]

The HABS photo was probably done much earlier, during the Depression when the government gave jobs to people with skills to record everything from historic buildings to slave narratives to artistic works.

Is the object that you are questioning the thing on the very bottom right? If so, it appears to be a spiral shelf to me. There is also something that appears to be a ball resting right against the stair riser. I have often thought how hard it must have been to climb that long flight of stairs multiple times each day. This, after the flight just to get in the front door.