Neat old piece by National Potteries from their Glass Division. I have a hunch that this is an old ceiling light globe cover. Measures approximately 4 1/4" tall and 5 1/2" across at its widest bulbous center.
It is in well preserved condition with no cracks or chips. There is some light hard water marking on the very bottom of the interior and so I am guessing that someone along the line has used this as a vase.
