Singer 413 bobbin problem

Question

I can't get the bobbin thread to come up through the thread plate. It doesn't even look like its doing anything in there. Isn't the bobbing supposed to be spinning or something? I got this machine second hand. It has been cleaned up and oiled and everything else about it seems fine. Maybe there is some kind of trick about getting the bobbin thread to pop up--it's an old machine-maybe they're different? Thanks for any help/advice you can give.