Roundsman

A laborer in need of help, who was sent round from one farmer to another for employment, partly at the expense of the farmer and partly at the cost of the village. Also, a policeman who patrols a city at night, making the rounds.

"Do you ever get aground on the alligators now?"
"Oh, no! it hasn't happened for years."
"Well, then, why do they still keep the alligator-boats in service?"
"Just for police duty--nothing more. They merely go up and down now and then. The present generation of alligators know them as easy as a burglar knows a roundsman; when they see one coming, they break camp and go for the woods."

Mark Twain, Life on the Mississippi (1883).