May be part of the internal gearing or cap piece to an early example of a fire escape device. A patent search on the date came back with the following result from the same date in 1879 from a E.M. Ball improving upon earlier designs.
Take a look at Figure 3 and specifically the item labeled "B" it looks like your item (without the patent date of course) and maybe the other tip piece of the circlet fell off.
Just a guess, could be something else but have a look. Click on the schematic image to enlarge