My mother used to tell a story about one time when she accidently made some delicate orange wine.  She had acquired a quantity of orange juice which she stored in an old milk can on rockers and tucked away in the cold cellar and then forgot.  When she later remembered it, it had fermented into a lovely tasty wine.  I was just thinking about that story and a question occurred to me that I never thought to ask her.  Why was the milk can on rockers?  I've never seen one like that.  Hers was something she found in the basement of a parsonage she and my dad were living in, in a small town in Maine in the 1930's.  Has anyone heard of an old-fashioned dairy process that involves a milk can on rockers?  Or have you seen one like that?

Buckeye Girl, I bet you're right that it was somebody's homemade attempt at a labor-saving butter churn.  Butter churn was my first thought, but I've never seen a picture of one that was a milk can on rockers and didn't even know if that would work.  Of course, we don't know if this one ever worked; maybe it ended up in the parsonage basement because it never worked well.