4. The Hashími Cubit

After the Moslem conquest of the countries of the Eastern great monarchies, the 25·26 inch standard of the Persian cubit was raised to 25·56 inches. This is the Hashími, or Hashemic cubit, named after Hashim, the chief of the Arab tribe to which the prophet Mahomed belonged. It is the cubit mentioned in the ‘Arabian Nights’ (524th night). But the cubit or the foot of the Nights, when not specified, is usually either of the Olympic or of Al-Mamūn’s standard. The increase of the Persian cubit was probably to bring it, together with the Beládi cubit and the Arshīn (to be described presently), into simple relation with a Qasáb of length slightly increased so that this should, for building and land measurement, be a common multiple of the three cubits. This is the Turkish qasáb, the qasáb qabáni = 153·45 inches.

7 Beládicubitsat21·888inches= 153·216inches.
6 Hashími„„25·56„= 153·36„
5-1/2 Arshīns„27·9„= 153·45„

By taking the 7 Beládi cubits at the equatorial standard of the Jewish cubit, 21·914 inches, they would give 153·34 inches, and taking 5-1/2 arshīns at the slightly diminished length of 27·88 inches, the qasáb would be an exact common multiple of them at 153·36 inches.

This qasáb can be divided into 6 Hashími cubits, or 12 feet, or 24 kubdehs (handshafts), or sexdecimally into 2 fathoms, 4 guz, 8 cubits, 16 spans. It is a mere coincidence that the old French foot, = 12·789 inches, was very approximately half a Hashími cubit.