Cubit

A cubit is the first recorded unit of length and was one of many different standards of measurement used through history. It was originally based on measuring by comparing to one's forearm length.
Cubits were employed through Antiquity, the Middle Ages up to Early Modern Times, especially for measuring cords and textiles, but also for timbers, stone and volumes of grain.
The Egyptian hieroglyph for the unit shows the symbol of a forearm, but it was rather longer than any actual forearms. The Egyptian cubit was subdivided into 7 palms of 4 digits each; surviving cubit rods are between 52.3 and 52.9 cm in length.
The distance between thumb and another finger to the elbow on an average person measures about 24 digits or 6 palms or 45 cm (18 inches.) This cubit is sometimes referred to as a "natural cubit" of 1½ feet and was used in the Roman system of measures and in different Greek systems.
Over time, various cubits and variations on the cubit have measured:
* 6 palms  =  24 digits, i.e. ~45.0 cm or 18 inches (1.50 ft)
* 7 palms, or 28 digits
* 8 palms  =  32 digits, i.e. ~60.0 cm or 24 inches (2.00 ft)
* 9 palms  =  36 digits, i.e. ~67.5 cm or 27 inches (2.25 ft)
From late Antiquity, the Roman ulna, a four-foot cubit (about 120 cm) is also attested. This length is the measure from a man's hip to the fingers of the outstretched opposite arm.
The English yard could be considered to be a type of cubit, measuring 12 palms, ~90 cm, or 36 inches (3.00 ft). This is the measure from the middle of a man's body to his fingers, always with outstretched arm. The English ell is essentially a kind of great cubit of 15 palms, 114 cm, or 45 inches (3.75 ft).
== The Egyptian royal cubit and Sumerian Nippur cubit ==
The earliest attested standard measure is from the Old Kingdom pyramids of Egypt and was called the royal cubit (mahe). The royal cubit was in length, and was subdivided into 7 palms of 4 digits each, for a 28-part measure in total. Evidence for the royal cubit unit is known from Old Kingdom architecture, from at least as early as the construction of the Step Pyramid of Djoser from around 2,700 BCE
In 1916, during the last years of the Ottoman Empire and in the middle of World War I, the German Assyriologist Eckhard Unger found a copper-alloy bar while excavating at Nippur. The bar dates from c. 2650 BCE. and Unger claimed it was used as a measurement standard. This irregularly formed and irregularly marked graduated rule supposedly defined the Sumerian cubit as about 518.6 mm or 20.4 inches, although this does not agree with more secure evidence from the statues of Guduea from the same region. A 30-digit cubit known as a kus was nevertheless known from the 2nd millennium B.C., with a digit-length of about 17.28 mm (more than 0.68 inch).
== Other important cubits ==
* The Roman cubitus is a six-palm cubit of about 444.5 mm. Twenty-four Roman cubits ≈ thirty-five English feet, so the Roman cubit is about 17.5 inches or 444.5 mm.
* The Greek pēchys (Greek; πῆχυς) was also a 24-digit cubit. So, the kyrēnaikos pēchys ("Cyrenaican cubit") measured about 463.1 mm and the metrios pēchys ("middle cubit") about 474.2 mm; respectively roughly and Roman cubits. Other Greek cubits based on different digit measures of other city-states are less important. The Greek 40-digit-measure, called bēma, corresponds to the Latin gradus, the step or half-a-pace.
* The Arabic Hashimi cubit of about 650.2 mm (25.6 inches) is considered to measure two French feet. Since the established ratio between the French and English foot is about 16 to 15, one can give following equation:  5 Hashimi cubits ≈ 10 French feet ≈ 128 English inches. Also the length of 256 Roman cubits and the length of 175 Hashimi cubits are nearly equivalent.
* The guard cubit (Arabic: ammatu rabitu) measured about 555.6 mm; of the Roman cubit. Therefore: 96 guard cubits ≈ 120 Roman cubits ≈ 175 English feet.
* The Arabic nil cubit (or black cubit) measured about 540.2 mm. This means 28 (later called) Greek digits of the kyrēnaikos pēchys ≈ of a Roman foot or just 308.7 mm. Thus 175 Roman cubits ≈ 144 black cubits.
* The Mesopotamian cubit measured about 533.4 mm, Roman cubit. Thus, 20 Mesopotamian cubits ≈ 24 Roman cubits ≈ 35 English feet.
* The Babylonian cubit (or cubit of Lagash) measured about 496.1 mm. Also a Babylonian trade cubit existed, nine-tenths of the normal cubit, i.e. 446.5 mm. The Babylonian cubit is of the royal cubit. 160 Babylonian trade cubits ≈ 144 Babylonian cubits ≈ 135 Egyptian royal cubits. (The royal cubit ≈ 529.2 mm. See above.)
*The (Pergamon) cubit 520.9 mm or of the Roman cubit.
*The (Salamis) cubit 484.0 mm or of the Roman cubit.
*The (Persia) cubit of about 500.1 mm or of the Roman cubit, which is also of the guard cubit.
*The (England) cubit 45.72 cm or 457.2mm
*The (Thai) cubit known as the (Thai: ศอก sok), meaning elbow, equals 500 mm and consists of two (คืบ kheup) or palm spans of 250 mm each.
* In Izapa, a pre-Columbian Mesoamerican city, the measuring unit was equivalent to about 495 mm, very close to the Lagash cubit. This is probably a coincidence, since a diffusion of culture from Mesopotamia to Mesoamerica has not been conclusively demonstrated.
* The different Jewish cubits (Hebrew: אַמָּה ama) are generally borrowed either from Babylonians or Greeks or Romans. In ancient Israel during the First Temple period, the cubit was 428.1 mm (16.85 in.) (≈ Roman cubit). During the Second Temple period, a cubit of about 444.5 mm (17.5 in.) (≈ Roman cubit) was in general use, but in the sacred areas of the temple a special cubit of 437.6 mm (17.23 in.) seems to have been used instead (≈ Roman cubit).
==See also==
* Ancient Greek units of measurement
* Foot (unit)
* Pous
==Notes==
6. Skinner, 2006, p 31
== References ==
== Bibliography ==
*
* Petrie, Sir Flinders Pyramids and Temples of Gizeh (1881)
* Vormetrische Längeneinheiten by Rolf C. A. Rottländer, Rottenburg / Köln (also see Search-Engine).
* Recovery of the Ancient System of Length Units by Dieter Lelgemann, former Director of the Institute for Geodesy and Geo-Information Technology, TU Berlin.
* Sacred Geometry by Stephen Skinner, Sterling Publishing, 2006, ISBN 978-1-4027-6582-7
* On the Ancient Determination of Meridian Arc Length by Eratosthenes of Kyrene Dieter Lelgemann, WS – History of Surveying and Measurement, Athens, Greece, May 22–27, 2004.
* Knobloch, Eberhard, Dieter Lelgemann und Andreas Fuls: "Zur hellenistischen Methode der Bestimmung des Erdumfangs und zur Asienkarte des Klaudios Ptolemaios." published in zfv (Zeitschrift für Geodäsie, Geoinformation und Landmanagment) 128. Jahrgang, Heft 3/2003, S. 211-217.
*The Great Pyramid Decoded by Peter Lemesurier ISBN 0 900193 56 5
==External links==
* Measurements of the Nippur Ell, now in a museum in Istanbul (Turkey).
Category:Bible unit of measure