This vessel, blown like a miniature bottle has a high kicked-in base and when turned upside down it would form a goblet with a double wall. When the cavity between the walls is filled with liquid and the base stopped, the glass could give the illusion of being filled. Cf., Newark, no. 98 and R. W. Smith, The significance of Roman glass, Metropolitan Museum Bulletin 8, no. 2, 1949, illustration on p. 50