Modern equivalences
Measures of length
In Roman Antiquity, one used eleven measuring units: the finger, the palm, the foot, bent, the step, the double step, the pole (or decempeda) , the length of Arpent, the Stage, the thousand and the Mile.
For measurements smaller than the finger, the Romans spoke about a half-finger, a third of finger, a quarter of finger, etc the simple step was used little. The pole was generally equivalent to ten feet ( decempeda ). Towards the end of Antiquity, the land-surveyors used also a pole of thirteen Roman feet and half (216 fingers) or of a pole of twelve feet with 18 fingers, with always 216 fingers.
The Greeks called “pygme” (the front armlever: bent to the wrist) a “foot” of 18 fingers. It acts in fact of the “foot” ( better: pygme) known as of Charlemagne (18 × 18,525 mm = 333,45 mm), known and used several centuries before the birth of this one. This attribution is thus only legendary. Also in this same text of the end of Antiquity, one can quote: “ Ulna habet fags IIII ”. It is precisely about the Aune of François Ier (1540), which wanted to be exactly of four Roman feet. (4 × 29,64 cm = 118,56 cm)
The arpent, or more precisely a length of arpent , was used for primarily to calculate agrarian measurements. The stage is the eighth of the thousand. The Gallic mile (“ leuga gallica ”, de 2223 m) and the Gallo-Roman mile also coexisted with the thousand.
The value of the Roman foot
The traditional value of 296 mm for the Roman foot is certainly a good approximation. Scientific work undertaken during the second moist one of the twentieth century, inter alia by Rolf A.C. Rottländer of Tübingen, allots 296,2 mm to the Roman foot. Researchers D. Lelgemann and E. Knobloch of Berlin prefer the value 296,3 Misters But the improved usual value (round with a tenth of millimetre) should be at 296,4 mm , therefore some 0,07 % above the value found by Rottländer.
The ratios between the bent Roman one, the imperial English foot and the foot of the King de France were scientifically établies :
768 (= 24 X 32) bent Roman equalize 1120 (= 35 X 32) English imperial feet or 1050 (= 35 X 30) feet of King de France.
One respectively obtains like value of the historical Roman foot : approximately 296,078 mm or exactly 296,333 Misters According to the case, while referring or with the definition of the feet of the King going back to 1799, or with the definition of the foot of English compromise of 1959, one finds a value is of less 0,041 %, is moreover 0,045 % compared to the value of Rottländer.
But for a few years, a growing number of specialists have preferred even a value arbitrarily définie : 296 352 µm. This value has the double advantage of remaining at the same time in the fork of precision obtained by statistical methods of the researchers referred to above and of being the product of three simple prime numbers 7^3 X 3^3 X 2^5 in µm IF. This gives very simple values for this multitude of measurements old deduced from/to each other by simple ratios.
Certainly, in practice, the length of the historical Roman foot differed very slightly according to the times and the provinces. The same standard could, according to the types of carryforward and its wear, to give differences in the feet which took model on him, with a “normal” error of ± 0,17 %.
the good definition of Pes Romanus is:
“ the Roman foot is sixteen shares of divided by 28. ”
La division of the foot by twelve gives the ounce of the foot, in other words the inch . This last measuring unit length is typically medieval and was not use in Antiquity romaine.
not to be confused with the twelfth of the book or the ounce of the book, used by the Romans and often called ounce all court.
* THE GREAT GALLIC MILE. According to the searchs for Jacques Dassié (who thus prolongs work of Saint-Ferjeux 1852, Aurès 1852, Lièvre 1891 and Close-Arceduc 1964), as a Gaulle, a great mile of values included/understood in the beach 2450 + 50 m, according to the tribes, had course before the Roman conquest. This inaccuracy (+ 50 m) is completely voluntary. It is only the resultant of values of heterogeneous feet specific to each Gallic tribe, because there did not exist as a Gaulle of centralizing capacity, as in Rome.
This “Gallic mile” appears indirectly in official documents and it seems well to have existed. Dassié confirms it by the crossing of aerial observations and mentions raised on the milliary columns. In the publication of this interesting research, its author quotes two different values with this mile: 2415 m and 2436 Mr. () Further in his publication, it finds even at the Tongres one mile of a percent too long. Dassié specifies that this “Gallic mile” is perhaps even at the origin of the definition of the foot of Roy de France , then foot of Paris . Because dividing this mile by 7500 again, one finds this last with an error from only 0,34%. According to him, the traditional mile of 2222 m would result from the “romanisation” of the Gallic mile so that it corresponds to an easy multiple of the thousand. One mile (romanized) = 1,5 thousand. See: http://archaero.com/archeo103.htm Bib. DASSIÉ (J) " The great mile gauloise". GALLIA, volume 56,1999, p 285-311. CNRS EDITIONS, Paris, 2000.
Later on the correspondence of the mile was “one hour of way to foot”, whereas among Romans it corresponded to half.
Measurements of surface
Cubic measures
1. To measure the liquids:
the setier (lat. sextarius, in old French: “sextier” or sometimes, in an abusive way: “septier”) is the sixth share of the conge.
This last is the eighth share of the quadrantal amphora , i.e. cubic Roman foot.
2. To measure the dry matters (grains):
the Roman bushel is the cubic pes. The muid (lat. modius, C. - with-D. “measurement”) is one the third of the Roman bushel .
Measurements of mass
Roman system
Text of the Gromatici veteres
Roman land-surveyors (5th century after J. - C.):
French text
Note that there are some minor differences between the use of the weights and measures at the time traditional Roman and the appreciations expressed in this text dating from the end of Antiquity to the threshold of the Middle Ages. But the majority of measurements and also the names of the multiples of the ounce were known and used at least since the Roman Republic.
See too
- Centuriation Roman, delimitation precise of the grounds and cities Roman.
External bonds
the site of air archeology
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