Weights & Measures
Since the Roman system of weights
and measures is fairly complex and of limited interest to most readers
of Latin literature, and since only a few technical treatises (e.g.
works on agriculture [Cato, Varro, Columella], or architecture [Vitruvius],
or astronomy [Manilius] or medicine [Celsus]) require more than the
most basic knowledge of it, only minimal and miscellaneous information
is provided here. (Most people nowadays have only a general notion of
measurement. How much wood is in a cord, wool in a skein, oil in a barrel,
pickled pepper(s) in a peck, whiskey in a fifth? (A fifth, a measurement
for liquor mostly in the USA, is a fifth of a gallon (= four-fifths
of a quart[er of a gallon].) Might a Shetland pony be 18 hands, and
how is the measurement taken? How much bigger is a hectare than an acre?
Is 10 mph quicker than 10 knots, and why are knots so called? Which
weighs more, a ton or a tonne, 10 stone of feathers or 100 lbs of gold?)
amphora, -ae fem. 1 amphora. An amphora contained a Roman cubic foot, equivalent to about 26 litres, and was the basis of liquid measurement. It comprised 48 sextāriī (-ōrum masc. 2) or 8 congiī (-ōrum masc. 2). A standard model, the amphora Capitōlīna, was kept in the temple of Jupiter Optimus Maximus on the Capitol. Like some other Roman terms for weights and measures, amphora is Greek, just as we use the avoirdupois weight system and the Troy system may be named after Troyes in France. A platinum-iridium cylinder is kept at Sèvres as the international prototype for the kilogram, the basic unit of mass.
neut. 2. The iūgerum was the basis of square measurement.
It is often loosely translated as “acre”, but it contained 28,800
Roman square feet, and is therefore equivalent to about a quarter of
a hectare or three fifths of an acre.
iūgerum is cognate with “yoke” (which is the same word as
iugum, -ī neut. 2). It was explained in antiquity as the
amount of land which a pair of oxen could plough in a day; cf. “furlong”
= “as long as a furrow”. At one time, a hērēdium (-iī,
neut. 2), the amount of land that a peasant might normally inherit,
was reckoned at two iūgera. “Acre” and ager, agrī
masc. 2 “field” are cognate, but the earlier, Indo-European,
sense was, conversely, “wild place”. The Romans thought ager
was derived from agere, in the sense “do”; i.e. a place of
fem. 1. The libra was the basis for measuring weight. It approximated
to the modern pound, but its value varied significantly not only over
time but in different regions of the empire. libra give us our
modern abbreviation for the pound, lb. By extension, libra
also meant “pair of scales”. After the sacking of Rome c. 387 BC,
the Gauls agreed to leave on payment of 1,000 pounds of gold. While
the gold was being weighed, the Romans complained that the scales were
incorrect. The Gallic leader, Brennus, threw his sword on the scales,
crying vae victīs (“Woe to the conquered!”). (Brennus may
not have been his actual name, but rather a Celtic word for “king”,
just as the name of the Illyrian queen Teuta who opposed the Romans
in the next century may be simply a version of an Illyrian word for
masc. 2, equivalent to about 8.75 litres, was the basis of dry measurement.
It consisted of 16 sextāriī (-ōrum masc. 2).
masc. 4 “pace”. The Romans not generally being very tall, their
mile (mille passūs) was 1,618 yards long, as opposed to the
present 1,760 yards. Similarly, pes, pedis masc. 3 “foot”
was about 11 and a half inches. The milliārium aureum “Golden
Milestone” was a column covered in gilt bronze, erected in the forum
Romanum by Augustus in 20 BC, as the point from which the great roads
led out of the city. The Zero Milestone, a granite block, was dedicated
in Washington DC in 1923 on the model of the milliārium aureum.
fem. 1. A unit of weight and measurement. An uncia is the twelfth
part of both a pēs (foot) and a libra (pound), and the
source of both “inch” and “ounce”. The uncial script is common
in early manuscripts. The phrase unciālēs litteræ is first
attested in St. Jerome, and “is commonly explained as meaning ‘letters
of an inch long’; his use of the word is accompanied by the phrase
ut vulgō aiunt [as is commonly said], and the literal sense was
perhaps not seriously intended. The emendations initiālēs ‘initial’
and uncinālēs ‘hooked, bent’, have been suggested” (OED