What you have there is the operating part of a household kerosene lamp. In my early childhood that's all we had for light. I was raised on a farm and metal shortages from WWII kept electric lines from getting to us until 1952 ! That part sat on top of the base and held the glass chimney. It also held the wick. The knob you see sticking out adjusted the height of the wick.
The ones we (and our neighbors) had were like this one, still made by the same company (!), and they have become quite pricey.
http://www.aladdin-us.com/product/C6192