NOTE: The standard is the same on 4 different comports: Inverted Prism (aka), Plain with Keystone Finial (aka), Two Owls (aka), and World's Ugliest Comport (aka). King & Son remains high on the list of possible makers.
Sid Lethbridge - US Patent No. 320,915 was issued to John S. Dignam of London, Ontario, Canada on June 30, 1885. “A hollow transparent handle or cover knob adapted to receive and display an internal decoration to be attached to the dish or cover in such a way as to be readily removed”. The finial on this comport is a glass sphere with a threaded base that screws into a metal retainer. A cork is placed in the neck of the glass finial to hold the floral arrangement. This is a match for one of the two suggested configurations shown in the patent drawings.