Convert from gry to stadium

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 (stadium)
The stadium is a historic unit of distance originating in ancient Greece. Greek athletic fields were all of roughly the same size, and the stadion, equal to 600 podes (feet), was the traditional length of the field. Archaeological measurements show that the stadion was a little more than 200 yards or a little less than 200 meters. The stadion at Olympia, where the original Olympic Games were held, measures 630.8 feet or 192.3 meters; at Athens the stadion was 606.9 feet or 185.0 meters. Stadium is the Latin spelling; in the Roman world the stadium was equal to 625 Roman feet (pes) or 1/8 Roman mile. This is equivalent to 606.95 feet, 202.32 yards, or 185.00 meters. The plural is stadia.