What is this device attached to the seat-tube? I dug out my late Dad's bicycle. Dad used the bicycle during his medical school days in the late 1940s ... or so. The bicycle has accumulated sufficient rust that it is impossible to identify the manufacturer. 

What is this device attached to the seat-tube? It's upper portion appears to be spring-loaded..
It appears to be a clamp-on pump peg that got moved down out of the way either intentionally or from coming loose.