What does Ann Putnam mean when she tells Rebecca: "there are wheels within wheels in the village and fires within fires"?

Since Mrs. Putnam is an antagonist and Rebecca is a protagonist in the story, Mrs. Putnam is probably trying to threaten Rebecca.  Mrs. Putnam is jealous of Rebecca because Rebecca had so many children and Mrs. Putnam didn't.  Mrs. Putnam subtly tries to suggest that maybe Rebecca had help from the devil in having so many children.  She also is suggesting that there are mysterious forces operating beneath the surface of Salem, and maybe some of these forces and relationships among citizens have a hidden purpose.