2420. Distributives are used to denote an equal division among several
persons or things, and in expressions of multiplication: as,
#bīnī senātōrēs singulīs cohortibus praepositī#, L. 3, 69, 8, _two
senators were put over every cohort_: sometimes when #singulī# is added,
the cardinal is used, thus: #singulīs cēnsōribus dēnāriī trecentī
imperātī sunt#, _V._ 2, 137, _every censor was assessed 300 denars_.
#bis bīna#, _DN_. 2, 49, _twice two_. Poets use multiplication freely,
partly for variety, but mainly from metrical necessity.
2421. Distributives are also used with substantives which have no
singular, or which have a different meaning in the singular; but in this
use _one_ is always #ūnī#, not #singulī#, and _three_ is often #trīnī#,
not #ternī#: as,
#ut ūna castra iam facta ex bīnīs vidērentur#, Caes. _C._ 1, 74, 4, _so
that one camp seemed now to have been formed out of two_. #trīnīs
catēnīs vinctus#, 1, 53, 5, _in triple irons_. Similarly with things in
pairs, as: #bovēs bīnī#, Pl. _Pers._ 317, _a yoke of oxen_.
2422. Poets sometimes use the singular of distributives: as, #centēnāque
arbore flūctum verberat#, V. 10, 207, _and with a hundred beams at every
stroke the wave he smites_. #duplicī nātūrā et corpore bīnō#, Lucr. 5,
879, _twynatured and of body twain_. The plural is sometimes used in
verse for the cardinal: #centum bracchia . . . centēnāsque manūs#, V.
10, 565, _a hundred arms . . . and hundred hands_.