Fr. _verge_ reappears in the English form of ‘verge’ in the sense of a circle or ring, AS. gyrd, now ‘girth.’ The gyrd was a geard or yard bent into a hoop. Fr. _verge_ = ring was a verge or rod bent into a hoop or ring. Cf. Fr. _bague_, ring made by bending a rod or baguette into a hoop. The English sense of ‘verge’ = circle is seen in:
O would to God that the inclusive verge Of golden metal that must round my brow.
To the furthest verge That ever was survey’d by English eye.
The ‘verge’ of the King’s palace or court, sometimes stated as twelve leagues (of 1-1/2 miles), a circuit equal to about 3 miles in radius.
Orthodoxly A.S. _gaard_ is considered to be unconnected with _geard_, a yard or rod.
The Roman pertica was 10 feet; though it seems probable that there was also a customary rod of 12 feet.
The French perche was 6 ells of 4 Roman feet, double the presumed customary perch of Rome.
The Scots rod was 6 ells of 3 Rhineland feet.
The German and Norse ruthen are nearly always either of 12 or of 16 feet.
How came it that the English rod was fixed, about the time of Edward I, at 5-1/2 yards = 16-1/2 feet?
There is reason to believe that it was originally 5 yards, at first in Roman feet, then in Rhineland feet.
A length of 5 yards and 1 or 2 inches (= 1/(8 × 40) of the Roman mile) survives in the Dorsetshire ‘goad’ or ‘lug.’[19]
Whence the term ‘lug’ = rod? I venture a derivation:
2. Luggie (Sc.), a milking vessel with handles or lugs.
3. Lug, lugge, of land, that can be metely sown with a luggie of seed-corn.
4. Lug, the rod-length of the lug of land.
5. Lug, a rod, as for ‘waling’ fruit trees.
The Cornish rod or yard is 2 staves of 3 yards = 6 yards. There was, as late as 1540, a rod of 6 yards, ‘every pole containing eighten footes of the kinges standard.’
The rod of Guernsey, of Lancashire and of Ireland is 7 yards; it is the French perche of 20 pieds = 21·36 feet taken roughly at 21 English feet; this, and the Cheshire rod of 8 yards = 4 fathoms, are probably of Norman origin.
The English rod of pre-Norman and early Norman times was probably the Teutonic rod of 16 feet, as seen in the Roll of Battel Abbey. How did it become 16-1/2 feet?
I cannot absolutely solve the question; I can only offer the possible hypotheses: