“"I'm no gaun to let naebody see the letter," sobbed the boy, "till I gie't to Mr. Lovel, for I am a faithfu' servant o' the office—if it werena for the powny."
"Very right, my little man," said Ochiltree, turning the reluctant pony's head towards Monkbarns; "but we'll guide him atween us." …
[They met Lovel on the way, ] and Davie, who insisted upon a literal execution of his commission by going on to Monkbarns, was with difficulty prevailed upon to surrender the packet to its proper owner, although he met him a mile nearer than the place he had been directed to. "But my minnie said, I maun be sure to get twenty shillings and five shillings for the postage, and ten shillings and sixpence for the express—there's the paper."
"Let me see—let me see," said Oldbuck, putting on his spectacles, and examining the crumpled copy of regulations to which Davie appealed. "Express, per man and horse, one day, not to exceed ten shillings and sixpence. One day? why, it's not an hour—Man and horse? why, 'tis a monkey on a starved cat!"”

Vol. I, Ch.15.
The Antiquary (1816), On the postal service