Round

round  dealing,” honest trading; “round  sum,” a large sum. Synonymous also, in a slang sense, with square , which see.
to tell tales, to split , which see ; “to round  on a man,” to swear to him as being the person, &c. Synonymous with buff , which see. Also to turn round upon and abuse or rate. Shakspeare has rounding , whispering.

 (in the language of the street), the beat or usual walk of a costermonger to sell his stock. A term used by street folk generally.

“Watchmen, sometimes they made their sallies,And walk'd their rounds  through streets and allies.”
Ned Ward's Vulgus Britannicus 1710.

The word “beat” has, so far as our modern guardians are concerned, deposed “round.”