Convert from gry to rod [international]

Unit Definition (gry)
The gry is a proposed unit of distance in the English traditional system. The name was first used in June 1679 by the philosopher John Locke (1632-1704) as a unit equal to 0.001 foot, 0.01 inch, or 0.1 line in a decimalized distance system. (Thomas Jefferson, who was very familiar with Locke's writings, later proposed a similar system in the U.S., but he called 0.001 foot a point rather than a gry.) In 1813, the gry was revived in another decimal measurement scheme in Britain. All these ideas failed, but the gry had some limited use in the nineteenth century as a unit equal to 0.1 line or 1/120 inch (0.211 667 millimeter). Long forgotten, the gry recently came back into the limelight in connection with a puzzle, circulating on the Internet, which asked for three English words ending in -gry. The word "gry" is from the ancient Greek, where it meant "a trifling amount".

Unit Definition (rod [international])
The rod is a traditional unit of distance equal to 5.5 yards (16 feet 6 inches or exactly 5.0292 meters). The rod and the furlong were the basic distance units used by the Anglo-Saxon residents of England before the Norman conquest of 1066. The Saxons generally called this unit the gyrd, a word which comes down to us as the name of a different unit, the yard. "Rod" is another Saxon word which meant just what it means today: a straight stick. The Normans preferred to call the gyrd a pole or a perch (a word of French origin, meaning a pole; see perche). The length of the rod was well established at least as early as the eighth century. It may have originated as the length of an ox-goad, a pole used to control a team of 8 oxen (4 yokes). Scholars are not sure how the rod was related to shorter units. It may have been considered equal to 20 "natural" feet (actual foot lengths; see foot), or it may have been measured "by hand" as 30 shaftments. In any case, when the modern foot became established in the twelfth century, the royal government did not want to change the length of the rod, since that length was the basis of land measurement, land records, and taxes. Therefore the rod was redefined to equal 16.5 of the new feet. This length was called the "king's perch" at least as early as the time of King Richard the Lionheart (1198). Although rods and perches of other lengths were used locally in Britain, the king's perch eventually prevailed. The relationship between the rod and the other English distance units was confirmed again by the Parliamentary statute of 1592, which defined the statute mile to be either 320 rods or 1760 yards, thus forcing the rod to equal exactly 5.5 yards or 16.5 feet.