The metal bar at the bottom is what controls the speed....you push it forward to make the wheel go faster & pull it back to slow it down. Both the books you mentioned look interesting....I'll have to check them out.
Thank you for your help!
The wheel pictured below is my first potters wheel. My parents purchased it used in the mid 1970's. I've never seen another one quite like it and would love any information anyone could provide on it.