Common Greek foot

from Wikipedia, the free encyclopedia
This article or section needs to be revised. Please help to improve it , and then remove this flag.

The common Greek foot  - scientifically also called pous metrios - is a classic unit of length . It measures 16 fifteenth of a Roman foot , roughly 316.1 mm.

This Greek foot was also used in Austria as the Austrian foot . In ancient times it was divided into 16 fingers , in Austria - as was common in the Middle Ages - into 12 thumbs (inches).
The ratio of the pous metrios to the Kyrenean foot is 1024 to 1000.

Using statistical evaluations of old standards, an average Roman foot of 296.2 mm ± 0.5 mm was scientifically determined by Rottländer, Tübingen. Since the ancient measures of length were always derived from one another using simple ratios, modern metrologists today prefer an arbitrarily defined, modern, conventional value of exactly 2 2 × 3 3 × 5 −3 × 7 3  mm = 296.352 mm. This value is well within the range of variation established by Rottländer, but has the advantage of ensuring simple values ​​for the derived length measurements. Instead of individual, random roundings, this value means a "total rounding" of all ancient lengths.

The modern, theoretical value of the pous metrios is 16 × (296.352 / 15) mm = 316.1088 mm.

The Austrian 6-foot fathom was set at 1.89648384 m in 1871 when the decimal system was converted.
The legal Austrian “pous metrios” has - expressed in exponentiated prime numbers - the defined length of 2 3 × 3 0 × 5 −5 × 7 0  × 37 × 47 × 71 mm = 316.08064 mm. This value is around 99.991% of the modern definition value, so it was 28.16 µm shorter than this. The legal, Austrian value of the “pous metrios” includes the large prime numbers 37, 47 and 71, which in fact never appear in ancient ratios .

Ultimately, the Austrian legislation with its - for old measures - extremely small deviation of around 0.0089% only confirms the modern scientific definition using the four exponentiated but simple prime numbers: 2, 3, 5 and 7.
These ratios arise between the ancient 16th -Finger-foot, the 18-finger pygme , the 20-finger pygon , as well as the various cubits of 24, 28, 30 and 32 finger widths.

Before 1816 the same foot was also used in Prussia, in connection with the Prussian measures of measure. There it was 316.149145 mm; that is just under 0.0128% or around 40⅓ µm more than the modern, seven-smooth reference value.

Individual evidence

  1. ↑ Austrian National Library: "Law, with which a new measure and weight order is established" of July 23, 1871.  Reichsgesetzblatt 16/1872, Article IV, page 30.

See also

Pre-metric lengths

Web links