Dusty Day is a short magazine story.
Spencer is taking the Duke and Duchess of Boxford to the China Clay Pits. When the get there, the Duke and Duchess meet some of the workmen and get to watch the china clay being loaded into trucks. Then, the Duchess takes a short tour of the pits where she is told about all the stuff that china clay is needed for.
When the tour comes to an end, the Duke and Duchess say goodbye and get ready to board their coach. Suddenly, a cloud of dust from Bill and Ben's trucks of china clay cover Spencer, the Duke and the Duchess. Bill and Ben apologise, but the Duke and Duchess just laugh; they have seen a lot of things that day, but they didn't see that dust cloud until it was too late.