(A). A salt herring. When George IV. visited Glasgow some wag placed a salt herring on the iron guard of the carriage of a well-known magistrate who formed one of the deputation to receive him. I remember a similar joke played on a magistrate, because he said, during a time of great scarcity, he wondered why the poor did not eat salt herrings, which he himself found very appetising.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894