E pur si muove or Eppur si muove is a phrase attributed to the Italian mathematician, physicist and philosopher Galileo Galilei (1564–1642) in 1633 after being forced to recant his claims that the Earth moves around the Sun
The point is that the baker wants the wheat ground as before to give us the same bread his father used to make, thus the stones that grind the wheat must have a regular work that can only be obtained by the sails following the wind direction.