Английская Википедия:Arabic mile
Шаблон:Short description The Arab, Arabic, or Arabian mile (Шаблон:Lang-ar, al-mīl) was a historical Arabic unit of length. Its precise length is disputed, lying between Шаблон:Convert and Шаблон:Convert. It was used by medieval Arab geographers and astronomers. The predecessor of the modern nautical mile, it extended the Roman mile 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 4,000 cubits in an Arabic mile. If al-Farghani used the legal cubit as his unit of measurement, then an Arabic mile was 1,995 meters long. If he used al-Ma'mun's surveying cubit, it was 1,925 meters long or Шаблон:Convert[1]
During the Umayyad period (661–750), the "Umayyad mile" was roughly equivalent to Шаблон:Convert, or a little more than Шаблон:Convert, or about 2 biblical miles, for every Umayyad mile.[2]
Al-Ma'mun's arc measurement
Around 830 AD, Caliph Al-Ma'mun commissioned a group of Muslim astronomers and Muslim geographers to perform an arc measurement from Tadmur (Palmyra) to Raqqa, in modern Syria. They found the cities to be separated by one degree of latitude and the corresponding meridian arc distance to be 66⅔ Arabic miles and thus calculated the Earth's circumference to be Шаблон:Convert.[3] Using this measurement, knowing that earth's circumference is 40,007.683 km makes the Arabic mile little more than 1,666.994 metres. With Firuzabadi in his famous dictionary saying that a mile equals 3000 old dhira (ie cubit) this makes the dhira about 0.5556647 metres which is consistent with the tradition that kaaba height's is 27 dhira and its current height of 15 metres.
Another estimate given by his astronomers was 56⅔ Arabic miles (Шаблон:Convert per degree), which corresponds to a circumference of Шаблон:Convert, very close to the current values of Шаблон:Convert per degree and Шаблон:Convert circumference, respectively.[1][4]
See also
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.
- Шаблон:Citation
- ↑ 1,0 1,1 Edward S. Kennedy, Mathematical Geography, pp=187–8, in Шаблон:Harv
- ↑ See: p. 608 (note 11) in: Шаблон:Cite journal
- ↑ Gharā'ib al-funūn wa-mulah al-`uyūn (The Book of Curiosities of the Sciences and Marvels for the Eyes), 2.1 "On the mensuration of the Earth and its division into seven climes, as related by Ptolemy and others," (ff. 22b-23a)[1]
- ↑ 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)[2]
