The Arab, Arabic, or Arabian mile ( ar, الميل, ''al-mīl'') was a historical

Arabic unit The Ancient Arabic unit of measurements were a system of using units to associate with physical quantities. Arabic symbols are used to represent the values. The measurements were based on body measurements and common natural items. The length of for ...

of length. Its precise length is disputed, lying between 1.8 and 2.0 km. It was used by medieval Arab geographers and

astronomers An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either obse ...

. The predecessor of the modern nautical mile, it extended the

Roman mile The mile, sometimes the international mile or statute mile to distinguish it from other miles, is a British imperial unit and United States customary unit of distance; both are based on the older English unit of length equal to 5,280 Engli ...

to fit an astronomical approximation of 1 minute of an arc of latitude measured along a north–south meridian. The distance between two pillars whose latitudes differed by 1 degree in a north–south direction was measured using sighting pegs along a flat desert plane. There were 4000

cubit The cubit is an ancient unit of length based on the distance from the elbow to the tip of the middle finger. It was primarily associated with the Sumerians, Egyptians, and Israelites. The term ''cubit'' is found in the Bible regarding ...

s in an Arabic mile. If

al-Farghani Abū al-ʿAbbās Aḥmad ibn Muḥammad ibn Kathīr al-Farghānī ( ar, أبو العبّاس أحمد بن محمد بن كثير الفرغاني 798/800/805–870), also known as Alfraganus in the West, was an astronomer in the Abbasid court ...

used the legal cubit as his unit of measurement, then an Arabic mile was 1995 meters long. If he used al-Ma'mun's surveying cubit, it was 1925 meters long or 1.04 modern nautical miles. During the Umayyad period (661–750), the "Umayyad mile" was roughly equivalent to , or a little more than two

kilometers The kilometre ( SI symbol: km; or ), spelt kilometer in American English, is a unit of length in the International System of Units (SI), equal to one thousand metres (kilo- being the SI prefix for ). It is now the measurement unit used for ex ...

, or about 2

biblical mile Biblical mile () is a unit of distance on land, or linear measure, principally used by Jews during the Herodian dynasty to ascertain distances between cities and to mark the Sabbath limit, equivalent to about ⅔ of an English statute mile, or wh ...

s, for every Umayyad mile.

Al-Ma'mun's arc measurement

Around 830 AD, Caliph Al-Ma'mun commissioned a group of Muslim astronomers and

Muslim geographers Medieval Islamic geography and cartography refer to the study of geography and cartography in the Muslim world during the Islamic Golden Age (variously dated between the 8th century and 16th century). Muslim scholars made advances to the map-maki ...

to perform an

arc measurement Arc measurement, sometimes degree measurement (german: Gradmessung), is the astrogeodetic technique of determining of the radius of Earth – more specifically, the local Earth radius of curvature of the figure of the Earth – by relating the la ...

from Tadmur (

Palmyra Palmyra (; Palmyrene: () ''Tadmor''; ar, تَدْمُر ''Tadmur'') is an ancient city in present-day Homs Governorate, Syria. Archaeological finds date back to the Neolithic period, and documents first mention the city in the early secon ...

) to

Raqqa Raqqa ( ar, ٱلرَّقَّة, ar-Raqqah, also and ) (Kurdish: Reqa/ ڕەقە) is a city in Syria on the northeast bank of the Euphrates River, about east of Aleppo. It is located east of the Tabqa Dam, Syria's largest dam. The Hellenistic, ...

, in modern Syria. They found the cities to be separated by one degree of

latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...

and the corresponding meridian arc distance to be 66⅔ miles and thus calculated the Earth's circumference to be 24,000 miles. Another estimate given by his astronomers was 56⅔ Arabic miles (111.8 km per degree), which corresponds to a circumference of 40,248 km, very close to the current values of 111.3 km per degree and 40,068 km circumference, respectively.Edward S. Kennedy, ''Mathematical Geography'', pp=187–8, in '' Gharā'ib al-funūn wa-mulah al-+uyūn '', 2.1" On the mensuration of the Earth and its division into seven Climes, es related by Ptolemy and others, "(ff. 22b-23

/ref>

Notes

Bibliography

*Paul Lunde. “Al-Faraghani and the Short Degree.” The Middle East and the Age of Discovery Aramco World Magazine Exhibition Issue, 43:3. pp. 15–17. * {{DEFAULTSORT:Arab Mile Obsolete units of measurement Geography in the medieval Islamic world Units of length

Al-Ma'mun's arc measurement

See also

Notes

Bibliography