a Roman measure of land, which formed the basis of the
whole system of land measurement. The word actus
sometimes denotes a way between fields, along which cattle
could be driven (Dig. 8
, &c.). Varro (L. L.
asserts that the name of the measure was derived from this, but couples this
remark with an absurd derivation of ager: ut ager quo agi
poterat, sic qua agi actus.
According to Varro, Columella
(5.1, 5, on the authority of Varro) and Festus, s.v. the actus simplex
(Roman) feet long and 4 feet wide. The actus
or simply actus,
square of 120 feet each way, containing thus 14,400 square feet. Pliny
) says of it: actus in quo boves agerentur cum aratro uno impetu justo
(i.e. without turning) ; hic erat cxx pedum.
1.215) explains actus,
“the driving,” to be properly a measure of labour, denoting the
half-day's work, with reference to the marked division of the day in Italy
by the noon-tide siesta. The jugerum,
“yoking,” the double of the actus,
would thus denote the day's work. This is far more
probable than the earlier explanations. The actus
furnishes an example of the combination of the duodecimal
with the decimal system, its length being twelve times the standard DECEMPEDA
§ 6) says that the Gauls called the
actus quadratus, arepennis;
but this could
only be an approximate identification, for the actus
is somewhat smaller than the great French arpent
and much larger than the small arpent.
Niebuhr, Hist. of Rome,
vol. ii. Appendix I.)