Does anyone know any specifics on this lamp? It is inkstamp marked Pyrex Made In USA on the glass, and the lamp itself has a small PAT'D SEPT. 10 1907 on the part right near the wick. It looks like a paraffin candle inside, perhaps, and it is held in by a spring that can be removed by taking off the bottom cap.

All who have answered have said this is a caboose lamp. If you have more to add, please feel free to email. Thanks to those who provided the caboose lamp answer, too.