Re: Middle English purlewe land severed from an English royal forest by perambulation, from Anglo-French puralé perambulation, from Old French puraler to go through, from pur- for, through + aler to go -- more at PURCHASE

this is a little piece of common law that has passed away--(but it was also done in New England and in NY)

at certain intervales, owners were required to 'walk a boundry'. since deeds might mark that one person owned the land marked by the stream, and the oak tree, and bounded by church yard, etc..

the owners would walk the boundry, and make certain the stream hadn't gone dry, (or changed course) or otherwise changed, and when the oak tree died, or was hit by lightening, or some other calamity, a new 'boundry' point would be established.

by walking a boundry (and this is especially important in england) you could check and make sure that easements, or rights of way were not established, as well as make certain, where the boundry was.

fields and (now city plots!) all over england are encumbered with right of way easements..

people established shortcuts and made paths across a fields (or 'parks' as some country estates were called) and these paths are protected forever, once established, they can't be undone.
regularlly walking the boundry, could check to see were paths and shortcuts were being created, and the other could prevent them from becoming established (in law)

(as a recall, it takes 7 years adn a day of unencumbered access to be come established in old common law--but i could be wrong.)

NYC Law is that private streets, that permit public access, must be closed at least one day each year, or they become public access ways. (Rockefeller Center has several--and they all get closed several times a year!)